138821808 has 40 divisors (see below), whose sum is σ = 364708800. Its totient is φ = 45488704.

The previous prime is 138821783. The next prime is 138821831. The reversal of 138821808 is 808128831.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 21678 + ... + 27341.

It is an arithmetic number, because the mean of its divisors is an integer number (9117720).

Almost surely, 2^138821808 is an apocalyptic number.

It is an amenable number.

138821808 is an abundant number, since it is smaller than the sum of its proper divisors (225886992).

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

138821808 is a wasteful number, since it uses less digits than its factorization.

138821808 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 49089 (or 49083 counting only the distinct ones).

The product of its (nonzero) digits is 24576, while the sum is 39.

The square root of 138821808 is about 11782.2666749654. The cubic root of 138821808 is about 517.7886965319.

The spelling of 138821808 in words is "one hundred thirty-eight million, eight hundred twenty-one thousand, eight hundred eight".