640842520 has 16 divisors (see below), whose sum is σ = 1441895760. Its totient is φ = 256336992.

The previous prime is 640842497. The next prime is 640842533. The reversal of 640842520 is 25248046.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 8010492 + ... + 8010571.

It is an arithmetic number, because the mean of its divisors is an integer number (90118485).

Almost surely, 2^640842520 is an apocalyptic number.

It is an amenable number.

640842520 is an abundant number, since it is smaller than the sum of its proper divisors (801053240).

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

640842520 is a wasteful number, since it uses less digits than its factorization.

640842520 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 16021074 (or 16021070 counting only the distinct ones).

The product of its (nonzero) digits is 15360, while the sum is 31.

The square root of 640842520 is about 25314.8675682888. The cubic root of 640842520 is about 862.1518673429.

The spelling of 640842520 in words is "six hundred forty million, eight hundred forty-two thousand, five hundred twenty".