643939632 has 100 divisors (see below), whose sum is σ = 2130027856. Its totient is φ = 183980160.

The previous prime is 643939619. The next prime is 643939649. The reversal of 643939632 is 236939346.

643939632 is a `hidden beast` number, since 6 + 4 + 3 + 9 + 3 + 9 + 632 = 666.

It is a nude number because it is divisible by every one of its digits.

It is an unprimeable number.

It is a polite number, since it can be written in 19 ways as a sum of consecutive naturals, for example, 26419 + ... + 44562.

Almost surely, 2^643939632 is an apocalyptic number.

It is an amenable number.

643939632 is an abundant number, since it is smaller than the sum of its proper divisors (1486088224).

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

643939632 is a wasteful number, since it uses less digits than its factorization.

643939632 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 71008 (or 70993 counting only the distinct ones).

The product of its digits is 629856, while the sum is 45.

The square root of 643939632 is about 25375.9656367989. The cubic root of 643939632 is about 863.5385267133.

The spelling of 643939632 in words is "six hundred forty-three million, nine hundred thirty-nine thousand, six hundred thirty-two".