138877639 has 4 divisors (see below), whose sum is σ = 139022224. Its totient is φ = 138733056.

The previous prime is 138877637. The next prime is 138877643. The reversal of 138877639 is 936778831.

It is a happy number.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 138877639 - 2¹ = 138877637 is a prime.

It is a super-2 number, since 2×138877639² = 38573997228428642, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (138877637) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 70842 + ... + 72775.

It is an arithmetic number, because the mean of its divisors is an integer number (34755556).

Almost surely, 2^138877639 is an apocalyptic number.

138877639 is a deficient number, since it is larger than the sum of its proper divisors (144585).

138877639 is an equidigital number, since it uses as much as digits as its factorization.

138877639 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 144584.

The product of its digits is 1524096, while the sum is 52.

The square root of 138877639 is about 11784.6357177471. The cubic root of 138877639 is about 517.8581015399.

The spelling of 138877639 in words is "one hundred thirty-eight million, eight hundred seventy-seven thousand, six hundred thirty-nine".