639857167 has 4 divisors (see below), whose sum is σ = 673533880. Its totient is φ = 606180456.

The previous prime is 639857161. The next prime is 639857213. The reversal of 639857167 is 761758936.

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

It is a cyclic number.

It is not a de Polignac number, because 639857167 - 2¹⁵ = 639824399 is a prime.

It is a super-2 number, since 2×639857167² = 818834388322531778, 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 (639857161) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 16838328 + ... + 16838365.

It is an arithmetic number, because the mean of its divisors is an integer number (168383470).

Almost surely, 2^639857167 is an apocalyptic number.

639857167 is a deficient number, since it is larger than the sum of its proper divisors (33676713).

639857167 is a wasteful number, since it uses less digits than its factorization.

639857167 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 33676712.

The product of its digits is 1905120, while the sum is 52.

The square root of 639857167 is about 25295.3981387920. The cubic root of 639857167 is about 861.7097619992.

The spelling of 639857167 in words is "six hundred thirty-nine million, eight hundred fifty-seven thousand, one hundred sixty-seven".