9996979981 has 2 divisors, whose sum is σ = 9996979982. Its totient is φ = 9996979980.

The previous prime is 9996979901. The next prime is 9996979987. The reversal of 9996979981 is 1899796999.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 8329482756 + 1667497225 = 91266^2 + 40835^2 .

It is a cyclic number.

It is not a de Polignac number, because 9996979981 - 2²⁷ = 9862762253 is a prime.

It is a super-2 number, since 2×9996979981² (a number of 21 digits) contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 9996979898 and 9996979907.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (9996979987) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 4998489990 + 4998489991.

It is an arithmetic number, because the mean of its divisors is an integer number (4998489991).

Almost surely, 2^9996979981 is an apocalyptic number.

It is an amenable number.

9996979981 is a deficient number, since it is larger than the sum of its proper divisors (1).

9996979981 is an equidigital number, since it uses as much as digits as its factorization.

9996979981 is an evil number, because the sum of its binary digits is even.

The product of its digits is 178564176, while the sum is 76.

The square root of 9996979981 is about 99984.8987647635. The cubic root of 9996979981 is about 2154.2177870721.

The spelling of 9996979981 in words is "nine billion, nine hundred ninety-six million, nine hundred seventy-nine thousand, nine hundred eighty-one".