639779932 has 24 divisors (see below), whose sum is σ = 1285683840. Its totient is φ = 275502960.

The previous prime is 639779927. The next prime is 639779939. The reversal of 639779932 is 239977936.

It is a super-2 number, since 2×639779932² = 818636722779849248, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (639779939) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 381808 + ... + 383479.

It is an arithmetic number, because the mean of its divisors is an integer number (53570160).

Almost surely, 2^639779932 is an apocalyptic number.

It is an amenable number.

639779932 is an abundant number, since it is smaller than the sum of its proper divisors (645903908).

639779932 is a wasteful number, since it uses less digits than its factorization.

639779932 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 765321 (or 765319 counting only the distinct ones).

The product of its digits is 3857868, while the sum is 55.

The square root of 639779932 is about 25293.8714316334. The cubic root of 639779932 is about 861.6750892446.

The spelling of 639779932 in words is "six hundred thirty-nine million, seven hundred seventy-nine thousand, nine hundred thirty-two".