642971988 has 36 divisors (see below), whose sum is σ = 1640489760. Its totient is φ = 212319696.

The previous prime is 642971971. The next prime is 642971993. The reversal of 642971988 is 889179246.

642971988 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a tau number, because it is divible by the number of its divisors (36).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 79608 + ... + 87311.

It is an arithmetic number, because the mean of its divisors is an integer number (45569160).

Almost surely, 2^642971988 is an apocalyptic number.

It is an amenable number.

642971988 is an abundant number, since it is smaller than the sum of its proper divisors (997517772).

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

642971988 is a wasteful number, since it uses less digits than its factorization.

642971988 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 167036 (or 167031 counting only the distinct ones).

The product of its digits is 1741824, while the sum is 54.

The square root of 642971988 is about 25356.8923174746. The cubic root of 642971988 is about 863.1057652496.

The spelling of 642971988 in words is "six hundred forty-two million, nine hundred seventy-one thousand, nine hundred eighty-eight".