9992597981 has 2 divisors, whose sum is σ = 9992597982. Its totient is φ = 9992597980.

The previous prime is 9992597921. The next prime is 9992597983. The reversal of 9992597981 is 1897952999.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 7604712025 + 2387885956 = 87205^2 + 48866^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-9992597981 is a prime.

It is a super-2 number, since 2×9992597981² (a number of 21 digits) contains 22 as substring.

It is a Sophie Germain prime.

Together with 9992597983, it forms a pair of twin primes.

It is a Chen 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 (9992597983) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 4996298990 + 4996298991.

It is an arithmetic number, because the mean of its divisors is an integer number (4996298991).

Almost surely, 2^9992597981 is an apocalyptic number.

It is an amenable number.

9992597981 is a deficient number, since it is larger than the sum of its proper divisors (1).

9992597981 is an equidigital number, since it uses as much as digits as its factorization.

9992597981 is an evil number, because the sum of its binary digits is even.

The product of its digits is 33067440, while the sum is 68.

The square root of 9992597981 is about 99962.9830537284. The cubic root of 9992597981 is about 2153.9029866040.

The spelling of 9992597981 in words is "nine billion, nine hundred ninety-two million, five hundred ninety-seven thousand, nine hundred eighty-one".