138519891 has 12 divisors (see below), whose sum is σ = 200625568. Its totient is φ = 92096784.

The previous prime is 138519883. The next prime is 138519907. The reversal of 138519891 is 198915831.

It is not a de Polignac number, because 138519891 - 2³ = 138519883 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (138519851) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 17275 + ... + 23988.

Almost surely, 2^138519891 is an apocalyptic number.

138519891 is a deficient number, since it is larger than the sum of its proper divisors (62105677).

138519891 is a wasteful number, since it uses less digits than its factorization.

138519891 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 41642 (or 41639 counting only the distinct ones).

The product of its digits is 77760, while the sum is 45.

The square root of 138519891 is about 11769.4473532108. The cubic root of 138519891 is about 517.4130526752.

The spelling of 138519891 in words is "one hundred thirty-eight million, five hundred nineteen thousand, eight hundred ninety-one".