25641640 has 32 divisors (see below), whose sum is σ = 60732000. Its totient is φ = 9716544.

The previous prime is 25641617. The next prime is 25641643. The reversal of 25641640 is 4614652.

It is a junction number, because it is equal to n+sod(n) for n = 25641599 and 25641608.

It is not an unprimeable number, because it can be changed into a prime (25641643) 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, 16110 + ... + 17629.

It is an arithmetic number, because the mean of its divisors is an integer number (1897875).

Almost surely, 2^25641640 is an apocalyptic number.

25641640 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

25641640 is an abundant number, since it is smaller than the sum of its proper divisors (35090360).

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

25641640 is a wasteful number, since it uses less digits than its factorization.

25641640 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 33769 (or 33765 counting only the distinct ones).

The product of its (nonzero) digits is 5760, while the sum is 28.

The square root of 25641640 is about 5063.7574981431. The cubic root of 25641640 is about 294.8822281969.

The spelling of 25641640 in words is "twenty-five million, six hundred forty-one thousand, six hundred forty".