138723990 has 16 divisors (see below), whose sum is σ = 332937648. Its totient is φ = 36993056.

The previous prime is 138723979. The next prime is 138724021. The reversal of 138723990 is 99327831.

It is a Curzon number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 2312037 + ... + 2312096.

It is an arithmetic number, because the mean of its divisors is an integer number (20808603).

Almost surely, 2^138723990 is an apocalyptic number.

138723990 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

138723990 is an abundant number, since it is smaller than the sum of its proper divisors (194213658).

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

138723990 is a wasteful number, since it uses less digits than its factorization.

138723990 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4624143.

The product of its (nonzero) digits is 81648, while the sum is 42.

The square root of 138723990 is about 11778.1148746308. The cubic root of 138723990 is about 517.6670514859.

The spelling of 138723990 in words is "one hundred thirty-eight million, seven hundred twenty-three thousand, nine hundred ninety".