645593972 has 24 divisors (see below), whose sum is σ = 1234840320. Its totient is φ = 294007680.

The previous prime is 645593939. The next prime is 645593981. The reversal of 645593972 is 279395546.

It is a happy number.

It is a self number, because there is not a number n which added to its sum of digits gives 645593972.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 151022 + ... + 155237.

It is an arithmetic number, because the mean of its divisors is an integer number (51451680).

Almost surely, 2^645593972 is an apocalyptic number.

645593972 is a gapful number since it is divisible by the number (62) formed by its first and last digit.

It is an amenable number.

645593972 is a deficient number, since it is larger than the sum of its proper divisors (589246348).

645593972 is a wasteful number, since it uses less digits than its factorization.

645593972 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 306311 (or 306309 counting only the distinct ones).

The product of its digits is 2041200, while the sum is 50.

The square root of 645593972 is about 25408.5413198003. The cubic root of 645593972 is about 864.2773975685.

The spelling of 645593972 in words is "six hundred forty-five million, five hundred ninety-three thousand, nine hundred seventy-two".