138908520 has 192 divisors, whose sum is σ = 484323840. Its totient is φ = 35769600.

The previous prime is 138908519. The next prime is 138908531. The reversal of 138908520 is 25809831.

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 47 ways as a sum of consecutive naturals, for example, 301090 + ... + 301550.

It is an arithmetic number, because the mean of its divisors is an integer number (2522520).

Almost surely, 2^138908520 is an apocalyptic number.

138908520 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 138908520, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (242161920).

138908520 is an abundant number, since it is smaller than the sum of its proper divisors (345415320).

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

138908520 is a wasteful number, since it uses less digits than its factorization.

138908520 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 518 (or 502 counting only the distinct ones).

The product of its (nonzero) digits is 17280, while the sum is 36.

The square root of 138908520 is about 11785.9458678546. The cubic root of 138908520 is about 517.8964825468.

The spelling of 138908520 in words is "one hundred thirty-eight million, nine hundred eight thousand, five hundred twenty".