78097979 has 2 divisors, whose sum is σ = 78097980. Its totient is φ = 78097978.

The previous prime is 78097951. The next prime is 78097993. The reversal of 78097979 is 97979087.

It is a strong prime.

It is an emirp because it is prime and its reverse (97979087) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 78097979 - 2¹⁶ = 78032443 is a prime.

It is a Sophie Germain prime.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (78097939) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 39048989 + 39048990.

It is an arithmetic number, because the mean of its divisors is an integer number (39048990).

Almost surely, 2^78097979 is an apocalyptic number.

78097979 is a deficient number, since it is larger than the sum of its proper divisors (1).

78097979 is an equidigital number, since it uses as much as digits as its factorization.

78097979 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 2000376, while the sum is 56.

The square root of 78097979 is about 8837.3060940538. The cubic root of 78097979 is about 427.4446953752. Note that the first 3 decimals are identical.

The spelling of 78097979 in words is "seventy-eight million, ninety-seven thousand, nine hundred seventy-nine".