79845517978 has 16 divisors (see below), whose sum is σ = 123398663976. Its totient is φ = 38723887360.

The previous prime is 79845517949. The next prime is 79845518017. The reversal of 79845517978 is 87971554897.

It can be written as a sum of positive squares in 4 ways, for example, as 71263904209 + 8581613769 = 266953^2 + 92637^2 .

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 2800051 + ... + 2828422.

Almost surely, 2^79845517978 is an apocalyptic number.

79845517978 is a deficient number, since it is larger than the sum of its proper divisors (43553145998).

79845517978 is a wasteful number, since it uses less digits than its factorization.

79845517978 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5628689.

The product of its digits is 177811200, while the sum is 70.

The spelling of 79845517978 in words is "seventy-nine billion, eight hundred forty-five million, five hundred seventeen thousand, nine hundred seventy-eight".