642906879 has 8 divisors (see below), whose sum is σ = 894479232. Its totient is φ = 409969560.

The previous prime is 642906871. The next prime is 642906883. The reversal of 642906879 is 978609246.

It is a happy number.

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

It is not a de Polignac number, because 642906879 - 2³ = 642906871 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (642906871) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 4658677 + ... + 4658814.

It is an arithmetic number, because the mean of its divisors is an integer number (111809904).

Almost surely, 2^642906879 is an apocalyptic number.

642906879 is a gapful number since it is divisible by the number (69) formed by its first and last digit.

642906879 is a deficient number, since it is larger than the sum of its proper divisors (251572353).

642906879 is a wasteful number, since it uses less digits than its factorization.

642906879 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9317517.

The product of its (nonzero) digits is 1306368, while the sum is 51.

The square root of 642906879 is about 25355.6084328497. The cubic root of 642906879 is about 863.0766308284.

The spelling of 642906879 in words is "six hundred forty-two million, nine hundred six thousand, eight hundred seventy-nine".