21131013161 has 2 divisors, whose sum is σ = 21131013162. Its totient is φ = 21131013160.

The previous prime is 21131013097. The next prime is 21131013193. The reversal of 21131013161 is 16131013112.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 10916070400 + 10214942761 = 104480^2 + 101069^2 .

It is a cyclic number.

It is not a de Polignac number, because 21131013161 - 2⁶ = 21131013097 is a prime.

It is not a weakly prime, because it can be changed into another prime (21131013061) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10565506580 + 10565506581.

It is an arithmetic number, because the mean of its divisors is an integer number (10565506581).

Almost surely, 2^21131013161 is an apocalyptic number.

It is an amenable number.

21131013161 is a deficient number, since it is larger than the sum of its proper divisors (1).

21131013161 is an equidigital number, since it uses as much as digits as its factorization.

21131013161 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 108, while the sum is 20.

Adding to 21131013161 its reverse (16131013112), we get a palindrome (37262026273).

The spelling of 21131013161 in words is "twenty-one billion, one hundred thirty-one million, thirteen thousand, one hundred sixty-one".