21264315161 has 2 divisors, whose sum is σ = 21264315162. Its totient is φ = 21264315160.

The previous prime is 21264315157. The next prime is 21264315167. The reversal of 21264315161 is 16151346212.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 19926145600 + 1338169561 = 141160^2 + 36581^2 .

It is a cyclic number.

It is not a de Polignac number, because 21264315161 - 2² = 21264315157 is a prime.

It is not a weakly prime, because it can be changed into another prime (21264315167) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10632157580 + 10632157581.

It is an arithmetic number, because the mean of its divisors is an integer number (10632157581).

Almost surely, 2^21264315161 is an apocalyptic number.

It is an amenable number.

21264315161 is a deficient number, since it is larger than the sum of its proper divisors (1).

21264315161 is an equidigital number, since it uses as much as digits as its factorization.

21264315161 is an evil number, because the sum of its binary digits is even.

The product of its digits is 8640, while the sum is 32.

The spelling of 21264315161 in words is "twenty-one billion, two hundred sixty-four million, three hundred fifteen thousand, one hundred sixty-one".