9978998831 has 2 divisors, whose sum is σ = 9978998832. Its totient is φ = 9978998830.

The previous prime is 9978998791. The next prime is 9978998833. The reversal of 9978998831 is 1388998799.

9978998831 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-9978998831 is a prime.

It is a super-2 number, since 2×9978998831² (a number of 21 digits) contains 22 as substring.

Together with 9978998833, it forms a pair of twin primes.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (9978998833) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 4989499415 + 4989499416.

It is an arithmetic number, because the mean of its divisors is an integer number (4989499416).

Almost surely, 2^9978998831 is an apocalyptic number.

9978998831 is a deficient number, since it is larger than the sum of its proper divisors (1).

9978998831 is an equidigital number, since it uses as much as digits as its factorization.

9978998831 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 70543872, while the sum is 71.

The square root of 9978998831 is about 99894.9389658956. The cubic root of 9978998831 is about 2152.9254447736.

The spelling of 9978998831 in words is "nine billion, nine hundred seventy-eight million, nine hundred ninety-eight thousand, eight hundred thirty-one".