643633896 has 16 divisors (see below), whose sum is σ = 1609084800. Its totient is φ = 214544624.

The previous prime is 643633883. The next prime is 643633927. The reversal of 643633896 is 698336346.

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, 13409016 + ... + 13409063.

It is an arithmetic number, because the mean of its divisors is an integer number (100567800).

Almost surely, 2^643633896 is an apocalyptic number.

It is an amenable number.

643633896 is an abundant number, since it is smaller than the sum of its proper divisors (965450904).

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

643633896 is a wasteful number, since it uses less digits than its factorization.

643633896 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 26818088 (or 26818084 counting only the distinct ones).

The product of its digits is 1679616, while the sum is 48.

The square root of 643633896 is about 25369.9407961469. The cubic root of 643633896 is about 863.4018386364.

The spelling of 643633896 in words is "six hundred forty-three million, six hundred thirty-three thousand, eight hundred ninety-six".