7978338791 has 2 divisors, whose sum is σ = 7978338792. Its totient is φ = 7978338790.

The previous prime is 7978338763. The next prime is 7978338793. The reversal of 7978338791 is 1978338797.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-7978338791 is a prime.

Together with 7978338793, it forms a pair of twin primes.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (7978338793) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 3989169395 + 3989169396.

It is an arithmetic number, because the mean of its divisors is an integer number (3989169396).

Almost surely, 2^7978338791 is an apocalyptic number.

7978338791 is a deficient number, since it is larger than the sum of its proper divisors (1).

7978338791 is an equidigital number, since it uses as much as digits as its factorization.

7978338791 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 16003008, while the sum is 62.

The square root of 7978338791 is about 89321.5471820770. The cubic root of 7978338791 is about 1998.1932676005.

The spelling of 7978338791 in words is "seven billion, nine hundred seventy-eight million, three hundred thirty-eight thousand, seven hundred ninety-one".