138129408 has 104 divisors (see below), whose sum is σ = 409550000. Its totient is φ = 46006272.

The previous prime is 138129389. The next prime is 138129419. The reversal of 138129408 is 804921831.

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

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, 109968 + ... + 111216.

Almost surely, 2^138129408 is an apocalyptic number.

138129408 is a gapful number since it is divisible by the number (18) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 138129408, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (204775000).

138129408 is an abundant number, since it is smaller than the sum of its proper divisors (271420592).

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

138129408 is an equidigital number, since it uses as much as digits as its factorization.

138129408 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1282 (or 1254 counting only the distinct ones).

The product of its (nonzero) digits is 13824, while the sum is 36.

The square root of 138129408 is about 11752.8468040726. The cubic root of 138129408 is about 516.9264050021.

It can be divided in two parts, 13812 and 9408, that added together give a triangular number (23220 = T₂₁₅).

The spelling of 138129408 in words is "one hundred thirty-eight million, one hundred twenty-nine thousand, four hundred eight".