12221981 has 2 divisors, whose sum is σ = 12221982. Its totient is φ = 12221980.

The previous prime is 12221971. The next prime is 12222013. The reversal of 12221981 is 18912221.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 7513081 + 4708900 = 2741^2 + 2170^2 .

It is a cyclic number.

It is not a de Polignac number, because 12221981 - 2⁶ = 12221917 is a prime.

It is a super-2 number, since 2×12221981² = 298753639128722, which contains 22 as substring.

It is a Chen prime.

It is a self number, because there is not a number n which added to its sum of digits gives 12221981.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (12221971) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 6110990 + 6110991.

It is an arithmetic number, because the mean of its divisors is an integer number (6110991).

Almost surely, 2^12221981 is an apocalyptic number.

It is an amenable number.

12221981 is a deficient number, since it is larger than the sum of its proper divisors (1).

12221981 is an equidigital number, since it uses as much as digits as its factorization.

12221981 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 576, while the sum is 26.

The square root of 12221981 is about 3495.9949942756. The cubic root of 12221981 is about 230.3459255835.

The spelling of 12221981 in words is "twelve million, two hundred twenty-one thousand, nine hundred eighty-one".