78866209979 has 4 divisors (see below), whose sum is σ = 78903536376. Its totient is φ = 78828883584.

The previous prime is 78866209963. The next prime is 78866210009. The reversal of 78866209979 is 97990266887.

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 78866209979 - 2⁴ = 78866209963 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (78866509979) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 18660029 + ... + 18664254.

It is an arithmetic number, because the mean of its divisors is an integer number (19725884094).

Almost surely, 2^78866209979 is an apocalyptic number.

78866209979 is a deficient number, since it is larger than the sum of its proper divisors (37326397).

78866209979 is a wasteful number, since it uses less digits than its factorization.

78866209979 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 37326396.

The product of its (nonzero) digits is 164602368, while the sum is 71.

The spelling of 78866209979 in words is "seventy-eight billion, eight hundred sixty-six million, two hundred nine thousand, nine hundred seventy-nine".