9898787981 has 2 divisors, whose sum is σ = 9898787982. Its totient is φ = 9898787980.

The previous prime is 9898787807. The next prime is 9898787989. The reversal of 9898787981 is 1897878989.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 9897265225 + 1522756 = 99485^2 + 1234^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-9898787981 is a prime.

It is a super-2 number, since 2×9898787981² (a number of 21 digits) contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 9898787899 and 9898787908.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (9898787989) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 4949393990 + 4949393991.

It is an arithmetic number, because the mean of its divisors is an integer number (4949393991).

Almost surely, 2^9898787981 is an apocalyptic number.

It is an amenable number.

9898787981 is a deficient number, since it is larger than the sum of its proper divisors (1).

9898787981 is an equidigital number, since it uses as much as digits as its factorization.

9898787981 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 146313216, while the sum is 74.

The square root of 9898787981 is about 99492.6528995986. The cubic root of 9898787981 is about 2147.1415397677.

The spelling of 9898787981 in words is "nine billion, eight hundred ninety-eight million, seven hundred eighty-seven thousand, nine hundred eighty-one".