21365111969 has 2 divisors, whose sum is σ = 21365111970. Its totient is φ = 21365111968.

The previous prime is 21365111951. The next prime is 21365112007. The reversal of 21365111969 is 96911156312.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 20245874944 + 1119237025 = 142288^2 + 33455^2 .

It is a cyclic number.

It is not a de Polignac number, because 21365111969 - 2¹² = 21365107873 is a prime.

It is a super-2 number, since 2×21365111969² (a number of 21 digits) contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (21365111939) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10682555984 + 10682555985.

It is an arithmetic number, because the mean of its divisors is an integer number (10682555985).

Almost surely, 2^21365111969 is an apocalyptic number.

It is an amenable number.

21365111969 is a deficient number, since it is larger than the sum of its proper divisors (1).

21365111969 is an equidigital number, since it uses as much as digits as its factorization.

21365111969 is an evil number, because the sum of its binary digits is even.

The product of its digits is 87480, while the sum is 44.

The spelling of 21365111969 in words is "twenty-one billion, three hundred sixty-five million, one hundred eleven thousand, nine hundred sixty-nine".