138959938491 has 32 divisors (see below), whose sum is σ = 208680192000. Its totient is φ = 81487161600.

The previous prime is 138959938471. The next prime is 138959938499. The reversal of 138959938491 is 194839959831.

It is not a de Polignac number, because 138959938491 - 2⁷ = 138959938363 is a prime.

It is not an unprimeable number, because it can be changed into a prime (138959938499) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 9745135 + ... + 9759383.

It is an arithmetic number, because the mean of its divisors is an integer number (6521256000).

Almost surely, 2^138959938491 is an apocalyptic number.

138959938491 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

138959938491 is a deficient number, since it is larger than the sum of its proper divisors (69720253509).

138959938491 is a wasteful number, since it uses less digits than its factorization.

138959938491 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 23827.

The product of its digits is 75582720, while the sum is 69.

The spelling of 138959938491 in words is "one hundred thirty-eight billion, nine hundred fifty-nine million, nine hundred thirty-eight thousand, four hundred ninety-one".