21222213161 has 2 divisors, whose sum is σ = 21222213162. Its totient is φ = 21222213160.

The previous prime is 21222213149. The next prime is 21222213241. The reversal of 21222213161 is 16131222212.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 21219457561 + 2755600 = 145669^2 + 1660^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21222213161 is a prime.

It is a super-2 number, since 2×21222213161² (a number of 21 digits) contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (21222212161) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10611106580 + 10611106581.

It is an arithmetic number, because the mean of its divisors is an integer number (10611106581).

Almost surely, 2^21222213161 is an apocalyptic number.

It is an amenable number.

21222213161 is a deficient number, since it is larger than the sum of its proper divisors (1).

21222213161 is an equidigital number, since it uses as much as digits as its factorization.

21222213161 is an evil number, because the sum of its binary digits is even.

The product of its digits is 576, while the sum is 23.

Adding to 21222213161 its reverse (16131222212), we get a palindrome (37353435373).

The spelling of 21222213161 in words is "twenty-one billion, two hundred twenty-two million, two hundred thirteen thousand, one hundred sixty-one".