25661616 has 20 divisors (see below), whose sum is σ = 66292632. Its totient is φ = 8553856.

The previous prime is 25661611. The next prime is 25661639. The reversal of 25661616 is 61616652.

It is not an unprimeable number, because it can be changed into a prime (25661611) 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, 267261 + ... + 267356.

Almost surely, 2^25661616 is an apocalyptic number.

It is an amenable number.

25661616 is an abundant number, since it is smaller than the sum of its proper divisors (40631016).

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

25661616 is a wasteful number, since it uses less digits than its factorization.

25661616 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 534628 (or 534622 counting only the distinct ones).

The product of its digits is 12960, while the sum is 33.

The square root of 25661616 is about 5065.7295624619. The cubic root of 25661616 is about 294.9587838616.

The spelling of 25661616 in words is "twenty-five million, six hundred sixty-one thousand, six hundred sixteen".