78394979 has 4 divisors (see below), whose sum is σ = 84425376. Its totient is φ = 72364584.

The previous prime is 78394963. The next prime is 78394991. The reversal of 78394979 is 97949387.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 78394979 - 2⁴ = 78394963 is a prime.

It is a super-2 number, since 2×78394979² = 12291545464820882, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (78394949) 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 3 ways as a sum of consecutive naturals, for example, 3015179 + ... + 3015204.

It is an arithmetic number, because the mean of its divisors is an integer number (21106344).

Almost surely, 2^78394979 is an apocalyptic number.

78394979 is a deficient number, since it is larger than the sum of its proper divisors (6030397).

78394979 is a wasteful number, since it uses less digits than its factorization.

78394979 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6030396.

The product of its digits is 3429216, while the sum is 56.

The square root of 78394979 is about 8854.0939118579. The cubic root of 78394979 is about 427.9858552841.

The spelling of 78394979 in words is "seventy-eight million, three hundred ninety-four thousand, nine hundred seventy-nine".