138818109 has 4 divisors (see below), whose sum is σ = 185090816. Its totient is φ = 92545404.

The previous prime is 138818101. The next prime is 138818111. The reversal of 138818109 is 901818831.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is not a de Polignac number, because 138818109 - 2³ = 138818101 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (138818101) 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, 23136349 + ... + 23136354.

It is an arithmetic number, because the mean of its divisors is an integer number (46272704).

Almost surely, 2^138818109 is an apocalyptic number.

It is an amenable number.

138818109 is a deficient number, since it is larger than the sum of its proper divisors (46272707).

138818109 is an equidigital number, since it uses as much as digits as its factorization.

138818109 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 46272706.

The product of its (nonzero) digits is 13824, while the sum is 39.

The square root of 138818109 is about 11782.1097007285. The cubic root of 138818109 is about 517.7840975489.

The spelling of 138818109 in words is "one hundred thirty-eight million, eight hundred eighteen thousand, one hundred nine".