642899656 has 64 divisors (see below), whose sum is σ = 1463961600. Its totient is φ = 258541632.

The previous prime is 642899651. The next prime is 642899683. The reversal of 642899656 is 656998246.

It is a happy number.

642899656 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a junction number, because it is equal to n+sod(n) for n = 642899597 and 642899606.

It is not an unprimeable number, because it can be changed into a prime (642899651) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 111025 + ... + 116671.

It is an arithmetic number, because the mean of its divisors is an integer number (22874400).

Almost surely, 2^642899656 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 642899656, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (731980800).

642899656 is an abundant number, since it is smaller than the sum of its proper divisors (821061944).

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

642899656 is a wasteful number, since it uses less digits than its factorization.

642899656 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5786 (or 5782 counting only the distinct ones).

The product of its digits is 5598720, while the sum is 55.

The square root of 642899656 is about 25355.4659984785. The cubic root of 642899656 is about 863.0733986206.

The spelling of 642899656 in words is "six hundred forty-two million, eight hundred ninety-nine thousand, six hundred fifty-six".