643637604 has 24 divisors (see below), whose sum is σ = 1515114720. Its totient is φ = 212646784.

The previous prime is 643637581. The next prime is 643637609. The reversal of 643637604 is 406736346.

It is not an unprimeable number, because it can be changed into a prime (643637609) 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 7 ways as a sum of consecutive naturals, for example, 235974 + ... + 238685.

It is an arithmetic number, because the mean of its divisors is an integer number (63129780).

Almost surely, 2^643637604 is an apocalyptic number.

It is an amenable number.

643637604 is an abundant number, since it is smaller than the sum of its proper divisors (871477116).

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

643637604 is a wasteful number, since it uses less digits than its factorization.

643637604 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 474779 (or 474777 counting only the distinct ones).

The product of its (nonzero) digits is 217728, while the sum is 39.

The square root of 643637604 is about 25370.0138746513. The cubic root of 643637604 is about 863.4034966638.

The spelling of 643637604 in words is "six hundred forty-three million, six hundred thirty-seven thousand, six hundred four".