25257640 has 32 divisors (see below), whose sum is σ = 58219560. Its totient is φ = 9856000.

The previous prime is 25257629. The next prime is 25257679. The reversal of 25257640 is 4675252.

It can be written as a sum of positive squares in 4 ways, for example, as 21548164 + 3709476 = 4642^2 + 1926^2 .

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 6061 + ... + 9340.

Almost surely, 2^25257640 is an apocalyptic number.

25257640 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

25257640 is an abundant number, since it is smaller than the sum of its proper divisors (32961920).

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

25257640 is a wasteful number, since it uses less digits than its factorization.

25257640 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 15453 (or 15449 counting only the distinct ones).

The product of its (nonzero) digits is 16800, while the sum is 31.

The square root of 25257640 is about 5025.6979614776. The cubic root of 25257640 is about 293.4028014993.

The spelling of 25257640 in words is "twenty-five million, two hundred fifty-seven thousand, six hundred forty".