21922731209 has 2 divisors, whose sum is σ = 21922731210. Its totient is φ = 21922731208.

The previous prime is 21922731137. The next prime is 21922731227. The reversal of 21922731209 is 90213722912.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 18704665225 + 3218065984 = 136765^2 + 56728^2 .

It is a cyclic number.

It is not a de Polignac number, because 21922731209 - 2²⁸ = 21654295753 is a prime.

It is a super-2 number, since 2×21922731209² (a number of 21 digits) contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (21922731239) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10961365604 + 10961365605.

It is an arithmetic number, because the mean of its divisors is an integer number (10961365605).

Almost surely, 2^21922731209 is an apocalyptic number.

It is an amenable number.

21922731209 is a deficient number, since it is larger than the sum of its proper divisors (1).

21922731209 is an equidigital number, since it uses as much as digits as its factorization.

21922731209 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 27216, while the sum is 38.

The spelling of 21922731209 in words is "twenty-one billion, nine hundred twenty-two million, seven hundred thirty-one thousand, two hundred nine".