21162506909 has 2 divisors, whose sum is σ = 21162506910. Its totient is φ = 21162506908.

The previous prime is 21162506891. The next prime is 21162506957. The reversal of 21162506909 is 90960526112.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 21118483684 + 44023225 = 145322^2 + 6635^2 .

It is a cyclic number.

It is not a de Polignac number, because 21162506909 - 2²⁸ = 20894071453 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21162502909) 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 as a sum of consecutive naturals, namely, 10581253454 + 10581253455.

It is an arithmetic number, because the mean of its divisors is an integer number (10581253455).

Almost surely, 2^21162506909 is an apocalyptic number.

It is an amenable number.

21162506909 is a deficient number, since it is larger than the sum of its proper divisors (1).

21162506909 is an equidigital number, since it uses as much as digits as its factorization.

21162506909 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 58320, while the sum is 41.

The spelling of 21162506909 in words is "twenty-one billion, one hundred sixty-two million, five hundred six thousand, nine hundred nine".