638499812 has 6 divisors (see below), whose sum is σ = 1117374678. Its totient is φ = 319249904.

The previous prime is 638499791. The next prime is 638499817. The reversal of 638499812 is 218994836.

It is a happy number.

It can be written as a sum of positive squares in only one way, i.e., 428655616 + 209844196 = 20704^2 + 14486^2 .

It is not an unprimeable number, because it can be changed into a prime (638499817) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 79812473 + ... + 79812480.

It is an arithmetic number, because the mean of its divisors is an integer number (186229113).

Almost surely, 2^638499812 is an apocalyptic number.

It is an amenable number.

638499812 is a deficient number, since it is larger than the sum of its proper divisors (478874866).

638499812 is a wasteful number, since it uses less digits than its factorization.

638499812 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 159624957 (or 159624955 counting only the distinct ones).

The product of its digits is 746496, while the sum is 50.

The square root of 638499812 is about 25268.5538169481. The cubic root of 638499812 is about 861.1000039870.

The spelling of 638499812 in words is "six hundred thirty-eight million, four hundred ninety-nine thousand, eight hundred twelve".