639919071 has 24 divisors (see below), whose sum is σ = 1011301200. Its totient is φ = 386697600.

The previous prime is 639919067. The next prime is 639919073. The reversal of 639919071 is 170919936.

639919071 is a `hidden beast` number, since 6 + 399 + 190 + 71 = 666.

It is not a de Polignac number, because 639919071 - 2² = 639919067 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (639919073) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 25291 + ... + 43811.

It is an arithmetic number, because the mean of its divisors is an integer number (42137550).

Almost surely, 2^639919071 is an apocalyptic number.

639919071 is a deficient number, since it is larger than the sum of its proper divisors (371382129).

639919071 is a wasteful number, since it uses less digits than its factorization.

639919071 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 18887 (or 18884 counting only the distinct ones).

The product of its (nonzero) digits is 91854, while the sum is 45.

The square root of 639919071 is about 25296.6217309743. The cubic root of 639919071 is about 861.7375502638.

The spelling of 639919071 in words is "six hundred thirty-nine million, nine hundred nineteen thousand, seventy-one".