25661538 has 24 divisors (see below), whose sum is σ = 63543168. Its totient is φ = 7331832.

The previous prime is 25661527. The next prime is 25661561. The reversal of 25661538 is 83516652.

25661538 is a `hidden beast` number, since 2 + 5 + 6 + 615 + 38 = 666.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 101706 + ... + 101957.

It is an arithmetic number, because the mean of its divisors is an integer number (2647632).

Almost surely, 2^25661538 is an apocalyptic number.

25661538 is an abundant number, since it is smaller than the sum of its proper divisors (37881630).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

25661538 is a wasteful number, since it uses less digits than its factorization.

25661538 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 203678 (or 203675 counting only the distinct ones).

The product of its digits is 43200, while the sum is 36.

The square root of 25661538 is about 5065.7218636637. The cubic root of 25661538 is about 294.9584850130.

The spelling of 25661538 in words is "twenty-five million, six hundred sixty-one thousand, five hundred thirty-eight".