138644520 has 384 divisors, whose sum is σ = 546652800. Its totient is φ = 27869184.

The previous prime is 138644509. The next prime is 138644531. The reversal of 138644520 is 25446831.

It is an interprime number because it is at equal distance from previous prime (138644509) and next prime (138644531).

It is an unprimeable number.

It is a polite number, since it can be written in 95 ways as a sum of consecutive naturals, for example, 1899204 + ... + 1899276.

It is an arithmetic number, because the mean of its divisors is an integer number (1423575).

Almost surely, 2^138644520 is an apocalyptic number.

138644520 is a gapful number since it is divisible by the number (10) 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 138644520, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (273326400).

138644520 is an abundant number, since it is smaller than the sum of its proper divisors (408008280).

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

138644520 is a wasteful number, since it uses less digits than its factorization.

138644520 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 137 (or 126 counting only the distinct ones).

The product of its (nonzero) digits is 23040, while the sum is 33.

The square root of 138644520 is about 11774.7407614775. The cubic root of 138644520 is about 517.5681816394.

The spelling of 138644520 in words is "one hundred thirty-eight million, six hundred forty-four thousand, five hundred twenty".