In decimal, 15 contains the digits 1 and 5 and is the result of adding together the integers from 1 to 5 (1 + 2 + 3 + 4 + 5 = 15). The only other number with this property (in decimal) is 27.

The X-15 achieved several speed and altitude marks in the early 1960s, reaching the limit with outer space (the Kármán line) and obtaining information that would be used in the design of …

Here, we will dive into the various properties, symbolism, and significance of the number 15, giving you a deeper understanding and appreciation for this intriguing numeral.

Oct 25, 2021 · OpenLearn turns 15 this week, so we’ve listed 15 facts about the number 15 – and linked each fact to a related FREE course, interactive or video.

Your guide to the number 15, an odd composite number composed of two distinct primes. Mathematical info, prime factorization, fun facts and numerical data for STEM, education and fun.

Jun 15, 2021 · The number 15 can be attributed to many areas like numerology, tradition, law, sports & games. Here are fifteen fun facts about the number 15.

Phosphorus (P) is the 15th chemical element.

Jun 3, 2023 · 15 is the third triangular number, meaning that it is the number of dots in a triangle with three dots on each side. The number 15 has been used in many famous works of art, …

Define 15. 15 synonyms, 15 pronunciation, 15 translation, English dictionary definition of 15. Noun 1. 15 - the cardinal number that is the sum of fourteen and one fifteen, XV large integer - an …

Nov 1, 2025 · 15 (previous 14, next 16) The following are equivalent forms as digits: