642637957 has 8 divisors (see below), whose sum is σ = 692375040. Its totient is φ = 592944240.

The previous prime is 642637921. The next prime is 642637979. The reversal of 642637957 is 759736246.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 642637957 - 2⁷ = 642637829 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 642637957.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (642637987) 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, 24144 + ... + 43222.

It is an arithmetic number, because the mean of its divisors is an integer number (86546880).

Almost surely, 2^642637957 is an apocalyptic number.

It is an amenable number.

642637957 is a deficient number, since it is larger than the sum of its proper divisors (49737083).

642637957 is a wasteful number, since it uses less digits than its factorization.

642637957 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 21683.

The product of its digits is 1905120, while the sum is 49.

The square root of 642637957 is about 25350.3048699616. The cubic root of 642637957 is about 862.9562750554.

The spelling of 642637957 in words is "six hundred forty-two million, six hundred thirty-seven thousand, nine hundred fifty-seven".