138220905 has 16 divisors (see below), whose sum is σ = 222747840. Its totient is φ = 73186368.

The previous prime is 138220891. The next prime is 138220939. The reversal of 138220905 is 509022831.

It is a happy number.

It is not a de Polignac number, because 138220905 - 2⁴ = 138220889 is a prime.

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 in 15 ways as a sum of consecutive naturals, for example, 31062 + ... + 35231.

It is an arithmetic number, because the mean of its divisors is an integer number (13921740).

Almost surely, 2^138220905 is an apocalyptic number.

138220905 is a gapful number since it is divisible by the number (15) formed by its first and last digit.

It is an amenable number.

138220905 is a deficient number, since it is larger than the sum of its proper divisors (84526935).

138220905 is a wasteful number, since it uses less digits than its factorization.

138220905 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 66440.

The product of its (nonzero) digits is 4320, while the sum is 30.

The square root of 138220905 is about 11756.7387059507. The cubic root of 138220905 is about 517.0405172600.

The spelling of 138220905 in words is "one hundred thirty-eight million, two hundred twenty thousand, nine hundred five".