25131561 has 24 divisors (see below), whose sum is σ = 41981184. Its totient is φ = 13255200.

The previous prime is 25131541. The next prime is 25131569. The reversal of 25131561 is 16513152.

It is not a de Polignac number, because 25131561 - 2⁵ = 25131529 is a prime.

It is not an unprimeable number, because it can be changed into a prime (25131569) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 4665 + ... + 8486.

It is an arithmetic number, because the mean of its divisors is an integer number (1749216).

Almost surely, 2^25131561 is an apocalyptic number.

25131561 is a gapful number since it is divisible by the number (21) formed by its first and last digit.

It is an amenable number.

25131561 is a deficient number, since it is larger than the sum of its proper divisors (16849623).

25131561 is a wasteful number, since it uses less digits than its factorization.

25131561 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 13181 (or 13174 counting only the distinct ones).

The product of its digits is 900, while the sum is 24.

The square root of 25131561 is about 5013.1388370960. The cubic root of 25131561 is about 292.9137923102.

The spelling of 25131561 in words is "twenty-five million, one hundred thirty-one thousand, five hundred sixty-one".