21713316161 has 2 divisors, whose sum is σ = 21713316162. Its totient is φ = 21713316160.

The previous prime is 21713316127. The next prime is 21713316169. The reversal of 21713316161 is 16161331712.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 18459298225 + 3254017936 = 135865^2 + 57044^2 .

It is a cyclic number.

It is not a de Polignac number, because 21713316161 - 2³⁴ = 4533446977 is a prime.

It is not a weakly prime, because it can be changed into another prime (21713316169) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10856658080 + 10856658081.

It is an arithmetic number, because the mean of its divisors is an integer number (10856658081).

Almost surely, 2^21713316161 is an apocalyptic number.

It is an amenable number.

21713316161 is a deficient number, since it is larger than the sum of its proper divisors (1).

21713316161 is an equidigital number, since it uses as much as digits as its factorization.

21713316161 is an evil number, because the sum of its binary digits is even.

The product of its digits is 4536, while the sum is 32.

Adding to 21713316161 its reverse (16161331712), we get a palindrome (37874647873).

The spelling of 21713316161 in words is "twenty-one billion, seven hundred thirteen million, three hundred sixteen thousand, one hundred sixty-one".