25515913 has 4 divisors (see below), whose sum is σ = 25658640. Its totient is φ = 25373188.

The previous prime is 25515887. The next prime is 25515923. The reversal of 25515913 is 31951552.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 25515913 - 2¹³ = 25507721 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (25515923) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 71095 + ... + 71452.

It is an arithmetic number, because the mean of its divisors is an integer number (6414660).

Almost surely, 2^25515913 is an apocalyptic number.

It is an amenable number.

25515913 is a deficient number, since it is larger than the sum of its proper divisors (142727).

25515913 is a wasteful number, since it uses less digits than its factorization.

25515913 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 142726.

The product of its digits is 6750, while the sum is 31.

The square root of 25515913 is about 5051.3278452304. The cubic root of 25515913 is about 294.3994793196.

It can be divided in two parts, 2551 and 5913, that added together give a square (8464 = 92²).

The spelling of 25515913 in words is "twenty-five million, five hundred fifteen thousand, nine hundred thirteen".