Numbers /15
How rare is 15?
15 scores 1,229 and sits in the Singular tier — 1 in 76,923 of all supported numbers score this high or higher. Everything below is computed from a complete analysis of all 1,000,001 numbers in range.
RNGdle.net’s own rarity score. Top <0.01% means that proportion of supported numbers scores at least this high. Every exact number has the same chance of being rolled. Same-length rank keeps the score and compares only numbers with 2 digits, including ties. How this differs from EP · Badge guide
These notes make the number easy to read, but they add no score unless a separately counted rarity signal appears below.
Equal to 2^k − 1, so its binary form is all ones.
Representation · signal frequency
One of only 90 two-digit numbers in range.
Range · signal frequency
This number's digits add up to an uncommon total.
Arithmetic · signal frequency
A sum 1 + 2 + … + k for some k.
Factorization · signal frequency
This number uses an uncommon count of distinct digits.
Repetition · signal frequency
Its binary form reads the same both ways.
Representation · signal frequency
The product of exactly two primes.
Factorization · signal frequency
Strongest signal: All ones in binary. It appears in 18 supported numbers and contributes +315 after correlation decay.
Why is 15 unusual? Only <0.01% of the 1,000,001 supported numbers receive an equal or higher rarity score. This number falls in the Singular tier. Scoring is grounded in the exact frequency of each detected trait — rarer traits carry more information and contribute more to the score.
Algorithm version 1.1.0
One digit away
One digit, +148 points.
Your number
15
Singular · Top <0.01%
Position 1: 1 → 5 · +148 points.
Gained: Fibonacci number, All digits identical, Palindrome, Digit sum 10, 1 distinct digit.
17 legal neighbours · same digit length · no leading zeros. This describes an alternative number, not the odds of your next roll.
Explore & share this near miss →Similar interesting numbers
Explore a shared pattern, a comparable score, or a mathematical relationship. Every link explains its connection to 15.
Shared patterns
Same length, nearby scores
Mathematical relationships
Patterns in this number
Each of these has its own page explaining how common the pattern is and why.
Semiprime Numbers
A semiprime is a product of exactly two primes, counted with multiplicity — 15 = 3 × 5, and 49 = 7 × 7 counts too.
Triangular Numbers
A triangular number counts the dots in a triangle: 1, 3, 6, 10, 15, 21 — each one the running total 1 + 2 + … + k.
Binary Palindromes
Written in base two, these numbers read the same forwards and backwards. 9 is 1001, and 585 is 1001001001.
Binary Repunits
These are the numbers one short of a power of two — 3, 7, 15, 31, 63, 1023 — whose binary form is nothing but ones.