138684923 has 4 divisors (see below), whose sum is σ = 149353008. Its totient is φ = 128016840.

The previous prime is 138684911. The next prime is 138684937. The reversal of 138684923 is 329486831.

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 138684923 - 2⁴ = 138684907 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (138684323) 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, 5334023 + ... + 5334048.

It is an arithmetic number, because the mean of its divisors is an integer number (37338252).

Almost surely, 2^138684923 is an apocalyptic number.

138684923 is a gapful number since it is divisible by the number (13) formed by its first and last digit.

138684923 is a deficient number, since it is larger than the sum of its proper divisors (10668085).

138684923 is a wasteful number, since it uses less digits than its factorization.

138684923 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10668084.

The product of its digits is 248832, while the sum is 44.

The square root of 138684923 is about 11776.4563006025. The cubic root of 138684923 is about 517.6184523516.

The spelling of 138684923 in words is "one hundred thirty-eight million, six hundred eighty-four thousand, nine hundred twenty-three".