138864218 has 4 divisors (see below), whose sum is σ = 208296330. Its totient is φ = 69432108.

The previous prime is 138864181. The next prime is 138864223. The reversal of 138864218 is 812468831.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in only one way, i.e., 85618009 + 53246209 = 9253^2 + 7297^2 .

It is an unprimeable number.

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 as a sum of consecutive naturals, namely, 34716053 + ... + 34716056.

Almost surely, 2^138864218 is an apocalyptic number.

138864218 is a deficient number, since it is larger than the sum of its proper divisors (69432112).

138864218 is an equidigital number, since it uses as much as digits as its factorization.

138864218 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 69432111.

The product of its digits is 73728, while the sum is 41.

The square root of 138864218 is about 11784.0662761205. The cubic root of 138864218 is about 517.8414192347.

The spelling of 138864218 in words is "one hundred thirty-eight million, eight hundred sixty-four thousand, two hundred eighteen".