138520919 has 4 divisors (see below), whose sum is σ = 141899520. Its totient is φ = 135142320.

The previous prime is 138520909. The next prime is 138520939. The reversal of 138520919 is 919025831.

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 138520919 - 2⁸ = 138520663 is a prime.

It is a super-2 number, since 2×138520919² = 38376090001209122, 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 (138520909) 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, 1689239 + ... + 1689320.

It is an arithmetic number, because the mean of its divisors is an integer number (35474880).

Almost surely, 2^138520919 is an apocalyptic number.

138520919 is a deficient number, since it is larger than the sum of its proper divisors (3378601).

138520919 is an equidigital number, since it uses as much as digits as its factorization.

138520919 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3378600.

The product of its (nonzero) digits is 19440, while the sum is 38.

The square root of 138520919 is about 11769.4910255287. The cubic root of 138520919 is about 517.4143326341.

The spelling of 138520919 in words is "one hundred thirty-eight million, five hundred twenty thousand, nine hundred nineteen".