78999979 has 2 divisors, whose sum is σ = 78999980. Its totient is φ = 78999978.

The previous prime is 78999961. The next prime is 79000007. The reversal of 78999979 is 97999987.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 78999979 - 2⁹ = 78999467 is a prime.

It is not a weakly prime, because it can be changed into another prime (78999959) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 39499989 + 39499990.

It is an arithmetic number, because the mean of its divisors is an integer number (39499990).

Almost surely, 2^78999979 is an apocalyptic number.

78999979 is a deficient number, since it is larger than the sum of its proper divisors (1).

78999979 is an equidigital number, since it uses as much as digits as its factorization.

78999979 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 23147208, while the sum is 67.

The square root of 78999979 is about 8888.1932359732. The cubic root of 78999979 is about 429.0840046825.

The spelling of 78999979 in words is "seventy-eight million, nine hundred ninety-nine thousand, nine hundred seventy-nine".