643582164 has 12 divisors (see below), whose sum is σ = 1501691744. Its totient is φ = 214527384.

The previous prime is 643582153. The next prime is 643582169. The reversal of 643582164 is 461285346.

It is a tau number, because it is divible by the number of its divisors (12).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (643582169) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 26815912 + ... + 26815935.

Almost surely, 2^643582164 is an apocalyptic number.

It is an amenable number.

643582164 is an abundant number, since it is smaller than the sum of its proper divisors (858109580).

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

643582164 is a wasteful number, since it uses less digits than its factorization.

643582164 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 53631854 (or 53631852 counting only the distinct ones).

The product of its digits is 138240, while the sum is 39.

The square root of 643582164 is about 25368.9212226299. The cubic root of 643582164 is about 863.3787060756.

The spelling of 643582164 in words is "six hundred forty-three million, five hundred eighty-two thousand, one hundred sixty-four".