21010211161 has 2 divisors, whose sum is σ = 21010211162. Its totient is φ = 21010211160.

The previous prime is 21010211137. The next prime is 21010211171. The reversal of 21010211161 is 16111201012.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 16967667600 + 4042543561 = 130260^2 + 63581^2 .

It is a cyclic number.

It is not a de Polignac number, because 21010211161 - 2⁹ = 21010210649 is a prime.

It is not a weakly prime, because it can be changed into another prime (21010211171) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10505105580 + 10505105581.

It is an arithmetic number, because the mean of its divisors is an integer number (10505105581).

Almost surely, 2^21010211161 is an apocalyptic number.

It is an amenable number.

21010211161 is a deficient number, since it is larger than the sum of its proper divisors (1).

21010211161 is an equidigital number, since it uses as much as digits as its factorization.

21010211161 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 24, while the sum is 16.

Adding to 21010211161 its reverse (16111201012), we get a palindrome (37121412173).

The spelling of 21010211161 in words is "twenty-one billion, ten million, two hundred eleven thousand, one hundred sixty-one".