138608820 has 240 divisors, whose sum is σ = 526901760. Its totient is φ = 29776896.

The previous prime is 138608807. The next prime is 138608839. The reversal of 138608820 is 28806831.

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 79 ways as a sum of consecutive naturals, for example, 192421 + ... + 193139.

It is an arithmetic number, because the mean of its divisors is an integer number (2195424).

Almost surely, 2^138608820 is an apocalyptic number.

138608820 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 138608820, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (263450880).

138608820 is an abundant number, since it is smaller than the sum of its proper divisors (388292940).

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

138608820 is a wasteful number, since it uses less digits than its factorization.

138608820 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 764 (or 753 counting only the distinct ones).

The product of its (nonzero) digits is 18432, while the sum is 36.

The square root of 138608820 is about 11773.2247069356. The cubic root of 138608820 is about 517.5237544231.

The spelling of 138608820 in words is "one hundred thirty-eight million, six hundred eight thousand, eight hundred twenty".