21232112309 has 2 divisors, whose sum is σ = 21232112310. Its totient is φ = 21232112308.

The previous prime is 21232112303. The next prime is 21232112323. The reversal of 21232112309 is 90321123212.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 21089429284 + 142683025 = 145222^2 + 11945^2 .

It is a cyclic number.

It is not a de Polignac number, because 21232112309 - 2¹² = 21232108213 is a prime.

It is a super-2 number, since 2×21232112309² (a number of 21 digits) contains 22 as substring.

It is a Sophie Germain prime.

It is a Curzon number.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21232112303) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10616056154 + 10616056155.

It is an arithmetic number, because the mean of its divisors is an integer number (10616056155).

Almost surely, 2^21232112309 is an apocalyptic number.

It is an amenable number.

21232112309 is a deficient number, since it is larger than the sum of its proper divisors (1).

21232112309 is an equidigital number, since it uses as much as digits as its factorization.

21232112309 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 1296, while the sum is 26.

The spelling of 21232112309 in words is "twenty-one billion, two hundred thirty-two million, one hundred twelve thousand, three hundred nine".