640708 has 12 divisors (see below), whose sum is σ = 1157632. Its totient is φ = 309960.

The previous prime is 640691. The next prime is 640727. The reversal of 640708 is 807046.

It is a hoax number, since the sum of its digits (25) coincides with the sum of the digits of its distinct prime factors.

It is an unprimeable number.

640708 is an untouchable number, because it is not equal to the sum of proper divisors of any number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2460 + ... + 2707.

2⁶⁴⁰⁷⁰⁸ is an apocalyptic number.

It is an amenable number.

640708 is a deficient number, since it is larger than the sum of its proper divisors (516924).

640708 is a wasteful number, since it uses less digits than its factorization.

640708 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5202 (or 5200 counting only the distinct ones).

The product of its (nonzero) digits is 1344, while the sum is 25.

The square root of 640708 is about 800.4423776887. The cubic root of 640708 is about 86.2091538020.

The spelling of 640708 in words is "six hundred forty thousand, seven hundred eight".