138655440 has 480 divisors, whose sum is σ = 604461312. Its totient is φ = 27648000.

The previous prime is 138655427. The next prime is 138655453. The reversal of 138655440 is 44556831.

It is a happy number.

138655440 is digitally balanced in base 3, because in such base it contains all the possibile digits an equal number of times.

It is an interprime number because it is at equal distance from previous prime (138655427) and next prime (138655453).

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

It is a junction number, because it is equal to n+sod(n) for n = 138655395 and 138655404.

It is a congruent number.

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, 2273010 + ... + 2273070.

Almost surely, 2^138655440 is an apocalyptic number.

138655440 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 138655440, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (302230656).

138655440 is an abundant number, since it is smaller than the sum of its proper divisors (465805872).

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

138655440 is a wasteful number, since it uses less digits than its factorization.

138655440 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 139 (or 130 counting only the distinct ones).

The product of its (nonzero) digits is 57600, while the sum is 36.

The square root of 138655440 is about 11775.2044568237. The cubic root of 138655440 is about 517.5817696177.

The spelling of 138655440 in words is "one hundred thirty-eight million, six hundred fifty-five thousand, four hundred forty".