21243001369 has 2 divisors, whose sum is σ = 21243001370. Its totient is φ = 21243001368.

The previous prime is 21243001333. The next prime is 21243001453. The reversal of 21243001369 is 96310034212.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 14765166144 + 6477835225 = 121512^2 + 80485^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21243001369 is a prime.

It is a super-2 number, since 2×21243001369² (a number of 21 digits) contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 21243001369.

It is not a weakly prime, because it can be changed into another prime (21243004369) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10621500684 + 10621500685.

It is an arithmetic number, because the mean of its divisors is an integer number (10621500685).

Almost surely, 2^21243001369 is an apocalyptic number.

It is an amenable number.

21243001369 is a deficient number, since it is larger than the sum of its proper divisors (1).

21243001369 is an equidigital number, since it uses as much as digits as its factorization.

21243001369 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 7776, while the sum is 31.

The spelling of 21243001369 in words is "twenty-one billion, two hundred forty-three million, one thousand, three hundred sixty-nine".