639664044100 has 27 divisors (see below), whose sum is σ = 1388088331357. Its totient is φ = 255862418480.

The previous prime is 639664044073. The next prime is 639664044127. The reversal of 639664044100 is 1440466936.

The square root of 639664044100 is 799790.

It is a perfect power (a square), and thus also a powerful number.

639664044100 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is an interprime number because it is at equal distance from previous prime (639664044073) and next prime (639664044127).

It can be written as a sum of positive squares in only one way, i.e., 230279055876 + 409384988224 = 479874^2 + 639832^2 .

It is a Duffinian number.

It is an unprimeable number.

It is a polite number, since it can be written in 8 ways as a sum of consecutive naturals, for example, 7957911 + ... + 8037889.

Almost surely, 2^639664044100 is an apocalyptic number.

639664044100 is the 799790-th square number.

It is an amenable number.

639664044100 is an abundant number, since it is smaller than the sum of its proper divisors (748424287257).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

639664044100 is an frugal number, since it uses more digits than its factorization.

639664044100 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 159972 (or 79986 counting only the distinct ones).

The product of its (nonzero) digits is 373248, while the sum is 43.

The spelling of 639664044100 in words is "six hundred thirty-nine billion, six hundred sixty-four million, forty-four thousand, one hundred".