639729927 has 8 divisors (see below), whose sum is σ = 947748080. Its totient is φ = 426486600.

The previous prime is 639729899. The next prime is 639729931. The reversal of 639729927 is 729927936.

It is not a de Polignac number, because 639729927 - 2⁶ = 639729863 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (639729947) 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, 11846824 + ... + 11846877.

It is an arithmetic number, because the mean of its divisors is an integer number (118468510).

Almost surely, 2^639729927 is an apocalyptic number.

639729927 is a deficient number, since it is larger than the sum of its proper divisors (308018153).

639729927 is a wasteful number, since it uses less digits than its factorization.

639729927 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 23693710 (or 23693704 counting only the distinct ones).

The product of its digits is 2571912, while the sum is 54.

The square root of 639729927 is about 25292.8829317656. The cubic root of 639729927 is about 861.6526392409.

The spelling of 639729927 in words is "six hundred thirty-nine million, seven hundred twenty-nine thousand, nine hundred twenty-seven".