9987992681 has 2 divisors, whose sum is σ = 9987992682. Its totient is φ = 9987992680.

The previous prime is 9987992671. The next prime is 9987992683. The reversal of 9987992681 is 1862997899.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 7346032681 + 2641960000 = 85709^2 + 51400^2 .

It is a cyclic number.

It is not a de Polignac number, because 9987992681 - 2⁶ = 9987992617 is a prime.

It is a super-2 number, since 2×9987992681² (a number of 21 digits) contains 22 as substring.

Together with 9987992683, it forms a pair of twin primes.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (9987992683) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 4993996340 + 4993996341.

It is an arithmetic number, because the mean of its divisors is an integer number (4993996341).

Almost surely, 2^9987992681 is an apocalyptic number.

It is an amenable number.

9987992681 is a deficient number, since it is larger than the sum of its proper divisors (1).

9987992681 is an equidigital number, since it uses as much as digits as its factorization.

9987992681 is an evil number, because the sum of its binary digits is even.

The product of its digits is 35271936, while the sum is 68.

The square root of 9987992681 is about 99939.9453722084. The cubic root of 9987992681 is about 2153.5720451850.

The spelling of 9987992681 in words is "nine billion, nine hundred eighty-seven million, nine hundred ninety-two thousand, six hundred eighty-one".