138557520 has 160 divisors (see below), whose sum is σ = 498182400. Its totient is φ = 35329536.

The previous prime is 138557509. The next prime is 138557539. The reversal of 138557520 is 25755831.

138557520 is a `hidden beast` number, since 1 + 3 + 85 + 57 + 520 = 666.

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 31 ways as a sum of consecutive naturals, for example, 48286 + ... + 51074.

It is an arithmetic number, because the mean of its divisors is an integer number (3113640).

Almost surely, 2^138557520 is an apocalyptic number.

138557520 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 138557520, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (249091200).

138557520 is an abundant number, since it is smaller than the sum of its proper divisors (359624880).

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

138557520 is a wasteful number, since it uses less digits than its factorization.

138557520 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2834 (or 2822 counting only the distinct ones).

The product of its (nonzero) digits is 42000, while the sum is 36.

The square root of 138557520 is about 11771.0458328901. The cubic root of 138557520 is about 517.4599002745.

The spelling of 138557520 in words is "one hundred thirty-eight million, five hundred fifty-seven thousand, five hundred twenty".