642756631 has 16 divisors (see below), whose sum is σ = 733598208. Its totient is φ = 557924800.

The previous prime is 642756623. The next prime is 642756671. The reversal of 642756631 is 136657246.

642756631 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a cyclic number.

It is not a de Polignac number, because 642756631 - 2³ = 642756623 is a prime.

It is a super-2 number, since 2×642756631² = 826272173388940322, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (642756671) 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, 6036 + ... + 36358.

It is an arithmetic number, because the mean of its divisors is an integer number (45849888).

Almost surely, 2^642756631 is an apocalyptic number.

642756631 is a deficient number, since it is larger than the sum of its proper divisors (90841577).

642756631 is a wasteful number, since it uses less digits than its factorization.

642756631 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 30422.

The product of its digits is 181440, while the sum is 40.

The square root of 642756631 is about 25352.6454438191. The cubic root of 642756631 is about 863.0093916242.

The spelling of 642756631 in words is "six hundred forty-two million, seven hundred fifty-six thousand, six hundred thirty-one".