639900290 has 16 divisors (see below), whose sum is σ = 1152194112. Its totient is φ = 255877104.

The previous prime is 639900269. The next prime is 639900293. The reversal of 639900290 is 92009936.

It is a super-2 number, since 2×639900290² = 818944762284168200, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (639900293) 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, 29177 + ... + 46163.

It is an arithmetic number, because the mean of its divisors is an integer number (72012132).

Almost surely, 2^639900290 is an apocalyptic number.

639900290 is a deficient number, since it is larger than the sum of its proper divisors (512293822).

639900290 is a wasteful number, since it uses less digits than its factorization.

639900290 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 20761.

The product of its (nonzero) digits is 26244, while the sum is 38.

The square root of 639900290 is about 25296.2505126748. The cubic root of 639900290 is about 861.7291197961.

The spelling of 639900290 in words is "six hundred thirty-nine million, nine hundred thousand, two hundred ninety".