638809102 has 16 divisors (see below), whose sum is σ = 1018204992. Its totient is φ = 299541760.

The previous prime is 638809063. The next prime is 638809103. The reversal of 638809102 is 201908836.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (638809103) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 23878 + ... + 42985.

It is an arithmetic number, because the mean of its divisors is an integer number (63637812).

Almost surely, 2^638809102 is an apocalyptic number.

638809102 is a deficient number, since it is larger than the sum of its proper divisors (379395890).

638809102 is a wasteful number, since it uses less digits than its factorization.

638809102 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 67163.

The product of its (nonzero) digits is 20736, while the sum is 37.

The square root of 638809102 is about 25274.6731333958. The cubic root of 638809102 is about 861.2390208008.

The spelling of 638809102 in words is "six hundred thirty-eight million, eight hundred nine thousand, one hundred two".