9978655231 has 2 divisors, whose sum is σ = 9978655232. Its totient is φ = 9978655230.

The previous prime is 9978655229. The next prime is 9978655273. The reversal of 9978655231 is 1325568799.

It is a weak prime.

It is an emirp because it is prime and its reverse (1325568799) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 9978655231 - 2¹ = 9978655229 is a prime.

It is a super-2 number, since 2×9978655231² (a number of 21 digits) contains 22 as substring.

Together with 9978655229, it forms a pair of twin primes.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (9978653231) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 4989327615 + 4989327616.

It is an arithmetic number, because the mean of its divisors is an integer number (4989327616).

Almost surely, 2^9978655231 is an apocalyptic number.

9978655231 is a deficient number, since it is larger than the sum of its proper divisors (1).

9978655231 is an equidigital number, since it uses as much as digits as its factorization.

9978655231 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 4082400, while the sum is 55.

The square root of 9978655231 is about 99893.2191442442. The cubic root of 9978655231 is about 2152.9007344232.

The spelling of 9978655231 in words is "nine billion, nine hundred seventy-eight million, six hundred fifty-five thousand, two hundred thirty-one".