9978655279 has 2 divisors, whose sum is σ = 9978655280. Its totient is φ = 9978655278.

The previous prime is 9978655273. The next prime is 9978655283. The reversal of 9978655279 is 9725568799.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 9978655279 - 2⁹ = 9978654767 is a prime.

It is a super-2 number, since 2×9978655279² (a number of 21 digits) contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (9978655273) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 4989327639 + 4989327640.

It is an arithmetic number, because the mean of its divisors is an integer number (4989327640).

Almost surely, 2^9978655279 is an apocalyptic number.

9978655279 is a deficient number, since it is larger than the sum of its proper divisors (1).

9978655279 is an equidigital number, since it uses as much as digits as its factorization.

9978655279 is an evil number, because the sum of its binary digits is even.

The product of its digits is 85730400, while the sum is 67.

The square root of 9978655279 is about 99893.2193845008. The cubic root of 9978655279 is about 2152.9007378752.

The spelling of 9978655279 in words is "nine billion, nine hundred seventy-eight million, six hundred fifty-five thousand, two hundred seventy-nine".