21759116909 has 2 divisors, whose sum is σ = 21759116910. Its totient is φ = 21759116908.

The previous prime is 21759116891. The next prime is 21759116957. The reversal of 21759116909 is 90961195712.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 20815275625 + 943841284 = 144275^2 + 30722^2 .

It is a cyclic number.

It is not a de Polignac number, because 21759116909 - 2²⁴ = 21742339693 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21759116209) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10879558454 + 10879558455.

It is an arithmetic number, because the mean of its divisors is an integer number (10879558455).

Almost surely, 2^21759116909 is an apocalyptic number.

It is an amenable number.

21759116909 is a deficient number, since it is larger than the sum of its proper divisors (1).

21759116909 is an equidigital number, since it uses as much as digits as its factorization.

21759116909 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 306180, while the sum is 50.

The spelling of 21759116909 in words is "twenty-one billion, seven hundred fifty-nine million, one hundred sixteen thousand, nine hundred nine".