21423430309 has 2 divisors, whose sum is σ = 21423430310. Its totient is φ = 21423430308.

The previous prime is 21423430291. The next prime is 21423430319. The reversal of 21423430309 is 90303432412.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 10992893409 + 10430536900 = 104847^2 + 102130^2 .

It is a cyclic number.

It is not a de Polignac number, because 21423430309 - 2²⁵ = 21389875877 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21423430319) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10711715154 + 10711715155.

It is an arithmetic number, because the mean of its divisors is an integer number (10711715155).

Almost surely, 2^21423430309 is an apocalyptic number.

It is an amenable number.

21423430309 is a deficient number, since it is larger than the sum of its proper divisors (1).

21423430309 is an equidigital number, since it uses as much as digits as its factorization.

21423430309 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 15552, while the sum is 31.

The spelling of 21423430309 in words is "twenty-one billion, four hundred twenty-three million, four hundred thirty thousand, three hundred nine".