138521567 has 4 divisors (see below), whose sum is σ = 139612416. Its totient is φ = 137430720.

The previous prime is 138521563. The next prime is 138521573. The reversal of 138521567 is 765125831.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 765125831 = 47 ⋅16279273.

It is a cyclic number.

It is not a de Polignac number, because 138521567 - 2² = 138521563 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 138521567.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (138521563) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 545234 + ... + 545487.

It is an arithmetic number, because the mean of its divisors is an integer number (34903104).

Almost surely, 2^138521567 is an apocalyptic number.

138521567 is a deficient number, since it is larger than the sum of its proper divisors (1090849).

138521567 is a wasteful number, since it uses less digits than its factorization.

138521567 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1090848.

The product of its digits is 50400, while the sum is 38.

The square root of 138521567 is about 11769.5185542995. The cubic root of 138521567 is about 517.4151394532.

The spelling of 138521567 in words is "one hundred thirty-eight million, five hundred twenty-one thousand, five hundred sixty-seven".