7999779917 has 2 divisors, whose sum is σ = 7999779918. Its totient is φ = 7999779916.

The previous prime is 7999779869. The next prime is 7999779919. The reversal of 7999779917 is 7199779997.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 7888814761 + 110965156 = 88819^2 + 10534^2 .

It is a cyclic number.

It is not a de Polignac number, because 7999779917 - 2²⁴ = 7983002701 is a prime.

Together with 7999779919, 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 (7999779919) by changing a digit.

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 as a sum of consecutive naturals, namely, 3999889958 + 3999889959.

It is an arithmetic number, because the mean of its divisors is an integer number (3999889959).

Almost surely, 2^7999779917 is an apocalyptic number.

It is an amenable number.

7999779917 is a deficient number, since it is larger than the sum of its proper divisors (1).

7999779917 is an equidigital number, since it uses as much as digits as its factorization.

7999779917 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 141776649, while the sum is 74.

The square root of 7999779917 is about 89441.4887901582. The cubic root of 7999779917 is about 1999.9816595818.

The spelling of 7999779917 in words is "seven billion, nine hundred ninety-nine million, seven hundred seventy-nine thousand, nine hundred seventeen".