645720632 has 16 divisors (see below), whose sum is σ = 1224331200. Its totient is φ = 319232320.

The previous prime is 645720629. The next prime is 645720671. The reversal of 645720632 is 236027546.

It is a junction number, because it is equal to n+sod(n) for n = 645720592 and 645720601.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 452744 + ... + 454167.

It is an arithmetic number, because the mean of its divisors is an integer number (76520700).

Almost surely, 2^645720632 is an apocalyptic number.

It is an amenable number.

645720632 is a deficient number, since it is larger than the sum of its proper divisors (578610568).

645720632 is a wasteful number, since it uses less digits than its factorization.

645720632 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 907006 (or 907002 counting only the distinct ones).

The product of its (nonzero) digits is 60480, while the sum is 35.

The square root of 645720632 is about 25411.0336665001. The cubic root of 645720632 is about 864.3339151433. Note that the first 3 decimals are identical.

The spelling of 645720632 in words is "six hundred forty-five million, seven hundred twenty thousand, six hundred thirty-two".