138578391 has 32 divisors (see below), whose sum is σ = 235566080. Its totient is φ = 78871968.

The previous prime is 138578389. The next prime is 138578393. The reversal of 138578391 is 193875831.

It is an interprime number because it is at equal distance from previous prime (138578389) and next prime (138578393).

It is not a de Polignac number, because 138578391 - 2¹ = 138578389 is a prime.

It is a hoax number, since the sum of its digits (45) coincides with the sum of the digits of its distinct prime factors.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (138578393) 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, 51030 + ... + 53676.

It is an arithmetic number, because the mean of its divisors is an integer number (7361440).

Almost surely, 2^138578391 is an apocalyptic number.

138578391 is a deficient number, since it is larger than the sum of its proper divisors (96987689).

138578391 is a wasteful number, since it uses less digits than its factorization.

138578391 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2940 (or 2934 counting only the distinct ones).

The product of its digits is 181440, while the sum is 45.

The square root of 138578391 is about 11771.9323392551. The cubic root of 138578391 is about 517.4858807322.

The spelling of 138578391 in words is "one hundred thirty-eight million, five hundred seventy-eight thousand, three hundred ninety-one".