21231010309 has 2 divisors, whose sum is σ = 21231010310. Its totient is φ = 21231010308.

The previous prime is 21231010291. The next prime is 21231010387. The reversal of 21231010309 is 90301013212.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 20178202500 + 1052807809 = 142050^2 + 32447^2 .

It is a cyclic number.

It is not a de Polignac number, because 21231010309 - 2⁵ = 21231010277 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 21231010309.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21231010399) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10615505154 + 10615505155.

It is an arithmetic number, because the mean of its divisors is an integer number (10615505155).

Almost surely, 2^21231010309 is an apocalyptic number.

It is an amenable number.

21231010309 is a deficient number, since it is larger than the sum of its proper divisors (1).

21231010309 is an equidigital number, since it uses as much as digits as its factorization.

21231010309 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 324, while the sum is 22.

The spelling of 21231010309 in words is "twenty-one billion, two hundred thirty-one million, ten thousand, three hundred nine".