21220233161 has 2 divisors, whose sum is σ = 21220233162. Its totient is φ = 21220233160.

The previous prime is 21220233137. The next prime is 21220233247. The reversal of 21220233161 is 16133202212.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 12563047225 + 8657185936 = 112085^2 + 93044^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21220233161 is a prime.

It is not a weakly prime, because it can be changed into another prime (21220233061) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10610116580 + 10610116581.

It is an arithmetic number, because the mean of its divisors is an integer number (10610116581).

Almost surely, 2^21220233161 is an apocalyptic number.

It is an amenable number.

21220233161 is a deficient number, since it is larger than the sum of its proper divisors (1).

21220233161 is an equidigital number, since it uses as much as digits as its factorization.

21220233161 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 864, while the sum is 23.

Adding to 21220233161 its reverse (16133202212), we get a palindrome (37353435373).

The spelling of 21220233161 in words is "twenty-one billion, two hundred twenty million, two hundred thirty-three thousand, one hundred sixty-one".