21329911609 has 2 divisors, whose sum is σ = 21329911610. Its totient is φ = 21329911608.

The previous prime is 21329911601. The next prime is 21329911633. The reversal of 21329911609 is 90611992312.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 16242228025 + 5087683584 = 127445^2 + 71328^2 .

It is a cyclic number.

It is not a de Polignac number, because 21329911609 - 2³ = 21329911601 is a prime.

It is not a weakly prime, because it can be changed into another prime (21329911601) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10664955804 + 10664955805.

It is an arithmetic number, because the mean of its divisors is an integer number (10664955805).

Almost surely, 2^21329911609 is an apocalyptic number.

It is an amenable number.

21329911609 is a deficient number, since it is larger than the sum of its proper divisors (1).

21329911609 is an equidigital number, since it uses as much as digits as its factorization.

21329911609 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 52488, while the sum is 43.

The spelling of 21329911609 in words is "twenty-one billion, three hundred twenty-nine million, nine hundred eleven thousand, six hundred nine".