12221009981 has 2 divisors, whose sum is σ = 12221009982. Its totient is φ = 12221009980.

The previous prime is 12221009951. The next prime is 12221010013. The reversal of 12221009981 is 18990012221.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 11770297081 + 450712900 = 108491^2 + 21230^2 .

It is an emirp because it is prime and its reverse (18990012221) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 12221009981 - 2⁶ = 12221009917 is a prime.

It is a super-2 number, since 2×12221009981² (a number of 21 digits) contains 22 as substring.

It is a Sophie Germain prime.

It is a Curzon number.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (12221009951) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 6110504990 + 6110504991.

It is an arithmetic number, because the mean of its divisors is an integer number (6110504991).

Almost surely, 2^12221009981 is an apocalyptic number.

It is an amenable number.

12221009981 is a deficient number, since it is larger than the sum of its proper divisors (1).

12221009981 is an equidigital number, since it uses as much as digits as its factorization.

12221009981 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 5184, while the sum is 35.

The spelling of 12221009981 in words is "twelve billion, two hundred twenty-one million, nine thousand, nine hundred eighty-one".