640453970 has 16 divisors (see below), whose sum is σ = 1241495640. Its totient is φ = 236475264.

The previous prime is 640453969. The next prime is 640453973. The reversal of 640453970 is 79354046.

640453970 is digitally balanced in base 6, because in such base it contains all the possibile digits an equal number of times.

It can be written as a sum of positive squares in 4 ways, for example, as 418652521 + 221801449 = 20461^2 + 14893^2 .

It is not an unprimeable number, because it can be changed into a prime (640453973) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 2463155 + ... + 2463414.

Almost surely, 2^640453970 is an apocalyptic number.

640453970 is a deficient number, since it is larger than the sum of its proper divisors (601041670).

640453970 is a wasteful number, since it uses less digits than its factorization.

640453970 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4926589.

The product of its (nonzero) digits is 90720, while the sum is 38.

The square root of 640453970 is about 25307.1920607562. The cubic root of 640453970 is about 861.9775880033.

The spelling of 640453970 in words is "six hundred forty million, four hundred fifty-three thousand, nine hundred seventy".