78717979 has 2 divisors, whose sum is σ = 78717980. Its totient is φ = 78717978.

The previous prime is 78717943. The next prime is 78718001. The reversal of 78717979 is 97971787.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 78717979 - 2⁹ = 78717467 is a prime.

It is a super-3 number, since 3×78717979³ (a number of 25 digits) contains 333 as substring.

It is not a weakly prime, because it can be changed into another prime (78717179) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 39358989 + 39358990.

It is an arithmetic number, because the mean of its divisors is an integer number (39358990).

Almost surely, 2^78717979 is an apocalyptic number.

78717979 is a deficient number, since it is larger than the sum of its proper divisors (1).

78717979 is an equidigital number, since it uses as much as digits as its factorization.

78717979 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 1555848, while the sum is 55.

The square root of 78717979 is about 8872.3153122508. The cubic root of 78717979 is about 428.5728401911.

The spelling of 78717979 in words is "seventy-eight million, seven hundred seventeen thousand, nine hundred seventy-nine".