640664970 has 32 divisors (see below), whose sum is σ = 1677378240. Its totient is φ = 155312640.

The previous prime is 640664963. The next prime is 640664993. The reversal of 640664970 is 79466046.

640664970 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a Curzon number.

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, 970375 + ... + 971034.

It is an arithmetic number, because the mean of its divisors is an integer number (52418070).

Almost surely, 2^640664970 is an apocalyptic number.

640664970 is an abundant number, since it is smaller than the sum of its proper divisors (1036713270).

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

640664970 is a wasteful number, since it uses less digits than its factorization.

640664970 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1941430.

The product of its (nonzero) digits is 217728, while the sum is 42.

The square root of 640664970 is about 25311.3604928696. The cubic root of 640664970 is about 862.0722382097.

The spelling of 640664970 in words is "six hundred forty million, six hundred sixty-four thousand, nine hundred seventy".