645039936 has 70 divisors (see below), whose sum is σ = 1912115810. Its totient is φ = 215011584.

The previous prime is 645039881. The next prime is 645039943. The reversal of 645039936 is 639930546.

It is a happy number.

It can be written as a sum of positive squares in only one way, i.e., 377913600 + 267126336 = 19440^2 + 16344^2 .

It is a junction number, because it is equal to n+sod(n) for n = 645039891 and 645039900.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 9 ways as a sum of consecutive naturals, for example, 57031 + ... + 67398.

Almost surely, 2^645039936 is an apocalyptic number.

It is an amenable number.

645039936 is an abundant number, since it is smaller than the sum of its proper divisors (1267075874).

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

645039936 is a wasteful number, since it uses less digits than its factorization.

645039936 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 124453 (or 124434 counting only the distinct ones).

The product of its (nonzero) digits is 524880, while the sum is 45.

The square root of 645039936 is about 25397.6364254629. The cubic root of 645039936 is about 864.0300915445.

The spelling of 645039936 in words is "six hundred forty-five million, thirty-nine thousand, nine hundred thirty-six".