21423344309 has 2 divisors, whose sum is σ = 21423344310. Its totient is φ = 21423344308.

The previous prime is 21423344197. The next prime is 21423344347. The reversal of 21423344309 is 90344332412.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 13265280625 + 8158063684 = 115175^2 + 90322^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21423344309 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21423349309) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10711672154 + 10711672155.

It is an arithmetic number, because the mean of its divisors is an integer number (10711672155).

Almost surely, 2^21423344309 is an apocalyptic number.

It is an amenable number.

21423344309 is a deficient number, since it is larger than the sum of its proper divisors (1).

21423344309 is an equidigital number, since it uses as much as digits as its factorization.

21423344309 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 62208, while the sum is 35.

The spelling of 21423344309 in words is "twenty-one billion, four hundred twenty-three million, three hundred forty-four thousand, three hundred nine".