25215 has 12 divisors (see below), whose sum is σ = 41352. Its totient is φ = 13120.

The previous prime is 25189. The next prime is 25219. The reversal of 25215 is 51252.

25215 = 69² + 70² + ... + 73².

It is not a de Polignac number, because 25215 - 2⁵ = 25183 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (15).

It is an Ulam number.

25215 is a lucky number.

It is a nialpdrome in base 15.

It is a junction number, because it is equal to n+sod(n) for n = 25194 and 25203.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (25219) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 595 + ... + 635.

It is an arithmetic number, because the mean of its divisors is an integer number (3446).

2²⁵²¹⁵ is an apocalyptic number.

25215 is a deficient number, since it is larger than the sum of its proper divisors (16137).

25215 is an equidigital number, since it uses as much as digits as its factorization.

25215 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 90 (or 49 counting only the distinct ones).

The product of its digits is 100, while the sum is 15.

The square root of 25215 is about 158.7923171945. The cubic root of 25215 is about 29.3237600762.

Subtracting from 25215 its sum of digits (15), we obtain a triangular number (25200 = T₂₂₄).

Multiplying 25215 by its sum of digits (15), we get a square (378225 = 615²).

25215 divided by its sum of digits (15) gives a square (1681 = 41²).

Adding to 25215 its reverse (51252), we get a palindrome (76467).

The spelling of 25215 in words is "twenty-five thousand, two hundred fifteen".