7797997978 has 32 divisors (see below), whose sum is σ = 12186417600. Its totient is φ = 3737873664.

The previous prime is 7797997967. The next prime is 7797997981. The reversal of 7797997978 is 8797997977.

It is a junction number, because it is equal to n+sod(n) for n = 7797997898 and 7797997907.

It is an unprimeable number.

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 15 ways as a sum of consecutive naturals, for example, 7727938 + ... + 7728946.

It is an arithmetic number, because the mean of its divisors is an integer number (380825550).

Almost surely, 2^7797997978 is an apocalyptic number.

7797997978 is a deficient number, since it is larger than the sum of its proper divisors (4388419622).

7797997978 is a wasteful number, since it uses less digits than its factorization.

7797997978 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1854.

The product of its digits is 882165816, while the sum is 79.

The square root of 7797997978 is about 88306.2737182359. The cubic root of 7797997978 is about 1983.0227931627.

Subtracting 7797997978 from its reverse (8797997977), we obtain a palindrome (999999999).

The spelling of 7797997978 in words is "seven billion, seven hundred ninety-seven million, nine hundred ninety-seven thousand, nine hundred seventy-eight".