640974 has 16 divisors (see below), whose sum is σ = 1289808. Its totient is φ = 212352.

The previous prime is 640973. The next prime is 640993. The reversal of 640974 is 479046.

It is a congruent number.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 640974.

It is not an unprimeable number, because it can be changed into a prime (640973) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1734 + ... + 2070.

It is an arithmetic number, because the mean of its divisors is an integer number (80613).

2⁶⁴⁰⁹⁷⁴ is an apocalyptic number.

640974 is an abundant number, since it is smaller than the sum of its proper divisors (648834).

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

640974 is a wasteful number, since it uses less digits than its factorization.

640974 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 659.

The product of its (nonzero) digits is 6048, while the sum is 30.

The square root of 640974 is about 800.6085185657. The cubic root of 640974 is about 86.2210825133.

The spelling of 640974 in words is "six hundred forty thousand, nine hundred seventy-four".