640537674 has 32 divisors (see below), whose sum is σ = 1514574720. Its totient is φ = 176699712.

The previous prime is 640537669. The next prime is 640537699. The reversal of 640537674 is 476735046.

It is a happy number.

It is a Harshad number since it is a multiple of its sum of digits (42).

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 261729 + ... + 264164.

It is an arithmetic number, because the mean of its divisors is an integer number (47330460).

Almost surely, 2^640537674 is an apocalyptic number.

640537674 is an abundant number, since it is smaller than the sum of its proper divisors (874037046).

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

640537674 is a wasteful number, since it uses less digits than its factorization.

640537674 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 525934.

The product of its (nonzero) digits is 423360, while the sum is 42.

The square root of 640537674 is about 25308.8457658582. The cubic root of 640537674 is about 862.0151383621.

The spelling of 640537674 in words is "six hundred forty million, five hundred thirty-seven thousand, six hundred seventy-four".