21808138122 has 12 divisors (see below), whose sum is σ = 47250965970. Its totient is φ = 7269379368.

The previous prime is 21808138109. The next prime is 21808138123. The reversal of 21808138122 is 22183180812.

21808138122 is a `hidden beast` number, since 2 + 180 + 81 + 381 + 22 = 666.

It can be written as a sum of positive squares in only one way, i.e., 21286518201 + 521619921 = 145899^2 + 22839^2 .

It is not an unprimeable number, because it can be changed into a prime (21808138123) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 605781597 + ... + 605781632.

Almost surely, 2^21808138122 is an apocalyptic number.

21808138122 is an abundant number, since it is smaller than the sum of its proper divisors (25442827848).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21808138122 is a wasteful number, since it uses less digits than its factorization.

21808138122 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1211563237 (or 1211563234 counting only the distinct ones).

The product of its (nonzero) digits is 12288, while the sum is 36.

The spelling of 21808138122 in words is "twenty-one billion, eight hundred eight million, one hundred thirty-eight thousand, one hundred twenty-two".