138561408 has 64 divisors (see below), whose sum is σ = 408958800. Its totient is φ = 46185984.

The previous prime is 138561383. The next prime is 138561419. The reversal of 138561408 is 804165831.

138561408 is a `hidden beast` number, since 1 + 38 + 5 + 614 + 0 + 8 = 666.

138561408 is digitally balanced in base 3, because in such base it contains all the possibile digits an equal number of times.

It is a tau number, because it is divible by the number of its divisors (64).

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a congruent number.

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, 16591 + ... + 23502.

Almost surely, 2^138561408 is an apocalyptic number.

138561408 is a gapful number since it is divisible by the number (18) formed by its first and last digit.

It is an amenable number.

138561408 is an abundant number, since it is smaller than the sum of its proper divisors (270397392).

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

138561408 is an equidigital number, since it uses as much as digits as its factorization.

138561408 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 40116 (or 40098 counting only the distinct ones).

The product of its (nonzero) digits is 23040, while the sum is 36.

The square root of 138561408 is about 11771.2109827324. The cubic root of 138561408 is about 517.4647402988.

The spelling of 138561408 in words is "one hundred thirty-eight million, five hundred sixty-one thousand, four hundred eight".