12971981221 has 2 divisors, whose sum is σ = 12971981222. Its totient is φ = 12971981220.

The previous prime is 12971981203. The next prime is 12971981233. The reversal of 12971981221 is 12218917921.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 12970704321 + 1276900 = 113889^2 + 1130^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-12971981221 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (12971988221) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 6485990610 + 6485990611.

It is an arithmetic number, because the mean of its divisors is an integer number (6485990611).

Almost surely, 2^12971981221 is an apocalyptic number.

It is an amenable number.

12971981221 is a deficient number, since it is larger than the sum of its proper divisors (1).

12971981221 is an equidigital number, since it uses as much as digits as its factorization.

12971981221 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 36288, while the sum is 43.

The spelling of 12971981221 in words is "twelve billion, nine hundred seventy-one million, nine hundred eighty-one thousand, two hundred twenty-one".