78987979 has 8 divisors (see below), whose sum is σ = 90406368. Its totient is φ = 67603200.

The previous prime is 78987977. The next prime is 78987983. The reversal of 78987979 is 97978987.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 78987979 - 2¹ = 78987977 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 78987979.

It is not an unprimeable number, because it can be changed into a prime (78987977) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 3142 + ... + 12955.

It is an arithmetic number, because the mean of its divisors is an integer number (11300796).

Almost surely, 2^78987979 is an apocalyptic number.

78987979 is a deficient number, since it is larger than the sum of its proper divisors (11418389).

78987979 is a wasteful number, since it uses less digits than its factorization.

78987979 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 16805.

The product of its digits is 16003008, while the sum is 64.

The square root of 78987979 is about 8887.5181575061. The cubic root of 78987979 is about 429.0622778042.

The spelling of 78987979 in words is "seventy-eight million, nine hundred eighty-seven thousand, nine hundred seventy-nine".