25640840 has 32 divisors (see below), whose sum is σ = 57862080. Its totient is φ = 10226112.

The previous prime is 25640831. The next prime is 25640863. The reversal of 25640840 is 4804652.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 16997 + ... + 18443.

It is an arithmetic number, because the mean of its divisors is an integer number (1808190).

Almost surely, 2^25640840 is an apocalyptic number.

25640840 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

25640840 is an abundant number, since it is smaller than the sum of its proper divisors (32221240).

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

25640840 is a wasteful number, since it uses less digits than its factorization.

25640840 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1901 (or 1897 counting only the distinct ones).

The product of its (nonzero) digits is 7680, while the sum is 29.

The square root of 25640840 is about 5063.6785048026. The cubic root of 25640840 is about 294.8791614633.

The spelling of 25640840 in words is "twenty-five million, six hundred forty thousand, eight hundred forty".