639166855 has 4 divisors (see below), whose sum is σ = 767000232. Its totient is φ = 511333480.

The previous prime is 639166841. The next prime is 639166861. The reversal of 639166855 is 558661936.

It is a happy number.

It is a semiprime because it is the product of two primes.

It is not a de Polignac number, because 639166855 - 2⁷ = 639166727 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 639166799 and 639166808.

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, 63916681 + ... + 63916690.

It is an arithmetic number, because the mean of its divisors is an integer number (191750058).

Almost surely, 2^639166855 is an apocalyptic number.

639166855 is a deficient number, since it is larger than the sum of its proper divisors (127833377).

639166855 is a wasteful number, since it uses less digits than its factorization.

639166855 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 127833376.

The product of its digits is 1166400, while the sum is 49.

The square root of 639166855 is about 25281.7494450048. The cubic root of 639166855 is about 861.3997643589.

The spelling of 639166855 in words is "six hundred thirty-nine million, one hundred sixty-six thousand, eight hundred fifty-five".