640520025 has 24 divisors (see below), whose sum is σ = 1060259520. Its totient is φ = 341202240.

The previous prime is 640520021. The next prime is 640520053. The reversal of 640520025 is 520025046.

It is not a de Polignac number, because 640520025 - 2² = 640520021 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 640519977 and 640520004.

It is not an unprimeable number, because it can be changed into a prime (640520021) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 64279 + ... + 73571.

It is an arithmetic number, because the mean of its divisors is an integer number (44177480).

Almost surely, 2^640520025 is an apocalyptic number.

It is an amenable number.

640520025 is a deficient number, since it is larger than the sum of its proper divisors (419739495).

640520025 is a wasteful number, since it uses less digits than its factorization.

640520025 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10225 (or 10220 counting only the distinct ones).

The product of its (nonzero) digits is 2400, while the sum is 24.

The square root of 640520025 is about 25308.4970908981. The cubic root of 640520025 is about 862.0072211359.

The spelling of 640520025 in words is "six hundred forty million, five hundred twenty thousand, twenty-five".