642661616 has 20 divisors (see below), whose sum is σ = 1249144752. Its totient is φ = 320301696.

The previous prime is 642661609. The next prime is 642661633. The reversal of 642661616 is 616166246.

642661616 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a Smith number, since the sum of its digits (38) coincides with the sum of the digits of its prime factors.

It is a self number, because there is not a number n which added to its sum of digits gives 642661616.

It is a congruent number.

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, 59156 + ... + 69171.

Almost surely, 2^642661616 is an apocalyptic number.

It is an amenable number.

642661616 is a deficient number, since it is larger than the sum of its proper divisors (606483136).

642661616 is a wasteful number, since it uses less digits than its factorization.

642661616 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 128648 (or 128642 counting only the distinct ones).

The product of its digits is 62208, while the sum is 38.

The square root of 642661616 is about 25350.7715069976. The cubic root of 642661616 is about 862.9668649642.

The spelling of 642661616 in words is "six hundred forty-two million, six hundred sixty-one thousand, six hundred sixteen".