138928919 has 4 divisors (see below), whose sum is σ = 138952944. Its totient is φ = 138904896.

The previous prime is 138928891. The next prime is 138928939. The reversal of 138928919 is 919829831.

It is a happy number.

138928919 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 919829831 = 113 ⋅8140087.

It is a cyclic number.

It is not a de Polignac number, because 138928919 - 2¹² = 138924823 is a prime.

It is a super-2 number, since 2×138928919² = 38602489069017122, 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 (138928939) 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, 2534 + ... + 16860.

It is an arithmetic number, because the mean of its divisors is an integer number (34738236).

Almost surely, 2^138928919 is an apocalyptic number.

138928919 is a deficient number, since it is larger than the sum of its proper divisors (24025).

138928919 is an equidigital number, since it uses as much as digits as its factorization.

138928919 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 24024.

The product of its digits is 279936, while the sum is 50.

The square root of 138928919 is about 11786.8112312024. The cubic root of 138928919 is about 517.9218326915.

The spelling of 138928919 in words is "one hundred thirty-eight million, nine hundred twenty-eight thousand, nine hundred nineteen".