138390990 has 64 divisors (see below), whose sum is σ = 346187520. Its totient is φ = 35375360.

The previous prime is 138390953. The next prime is 138390997. The reversal of 138390990 is 99093831.

It is a happy number.

It is a super-2 number, since 2×138390990² = 38304132226360200, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (138390997) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 71617 + ... + 73523.

It is an arithmetic number, because the mean of its divisors is an integer number (5409180).

Almost surely, 2^138390990 is an apocalyptic number.

138390990 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is a practical number, because each smaller number is the sum of distinct divisors of 138390990, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (173093760).

138390990 is an abundant number, since it is smaller than the sum of its proper divisors (207796530).

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

138390990 is a wasteful number, since it uses less digits than its factorization.

138390990 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2017.

The product of its (nonzero) digits is 52488, while the sum is 42.

The square root of 138390990 is about 11763.9699931613. The cubic root of 138390990 is about 517.2525083230.

The spelling of 138390990 in words is "one hundred thirty-eight million, three hundred ninety thousand, nine hundred ninety".