138263508 has 36 divisors (see below), whose sum is σ = 350056980. Its totient is φ = 46014336.

The previous prime is 138263473. The next prime is 138263537. The reversal of 138263508 is 805362831.

138263508 is a `hidden beast` number, since 13 + 8 + 2 + 635 + 0 + 8 = 666.

It can be written as a sum of positive squares in 2 ways, for example, as 14653584 + 123609924 = 3828^2 + 11118^2 .

It is a tau number, because it is divible by the number of its divisors (36).

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 11 ways as a sum of consecutive naturals, for example, 22816 + ... + 28232.

It is an arithmetic number, because the mean of its divisors is an integer number (9723805).

Almost surely, 2^138263508 is an apocalyptic number.

138263508 is a gapful number since it is divisible by the number (18) formed by its first and last digit.

It is an amenable number.

138263508 is an abundant number, since it is smaller than the sum of its proper divisors (211793472).

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

138263508 is a wasteful number, since it uses less digits than its factorization.

138263508 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6136 (or 6131 counting only the distinct ones).

The product of its (nonzero) digits is 34560, while the sum is 36.

The square root of 138263508 is about 11758.5504208640. The cubic root of 138263508 is about 517.0936332350.

The spelling of 138263508 in words is "one hundred thirty-eight million, two hundred sixty-three thousand, five hundred eight".