25521531 has 8 divisors (see below), whose sum is σ = 38889984. Its totient is φ = 14583720.

The previous prime is 25521521. The next prime is 25521553. The reversal of 25521531 is 13512552.

It is a happy number.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 25521531 - 2²² = 21327227 is a prime.

It is a super-2 number, since 2×25521531² = 1302697089167922, which contains 22 as substring.

It is a Smith number, since the sum of its digits (24) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is not an unprimeable number, because it can be changed into a prime (25521521) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 607635 + ... + 607676.

It is an arithmetic number, because the mean of its divisors is an integer number (4861248).

Almost surely, 2^25521531 is an apocalyptic number.

25521531 is a gapful number since it is divisible by the number (21) formed by its first and last digit.

25521531 is a deficient number, since it is larger than the sum of its proper divisors (13368453).

25521531 is a wasteful number, since it uses less digits than its factorization.

25521531 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1215321.

The product of its digits is 1500, while the sum is 24.

The square root of 25521531 is about 5051.8839060295. The cubic root of 25521531 is about 294.4210843327.

The spelling of 25521531 in words is "twenty-five million, five hundred twenty-one thousand, five hundred thirty-one".