7991216609 has 2 divisors, whose sum is σ = 7991216610. Its totient is φ = 7991216608.

The previous prime is 7991216551. The next prime is 7991216617. The reversal of 7991216609 is 9066121997.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 5111821009 + 2879395600 = 71497^2 + 53660^2 .

It is a cyclic number.

It is not a de Polignac number, because 7991216609 - 2¹² = 7991212513 is a prime.

It is not a weakly prime, because it can be changed into another prime (7991216509) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 3995608304 + 3995608305.

It is an arithmetic number, because the mean of its divisors is an integer number (3995608305).

Almost surely, 2^7991216609 is an apocalyptic number.

It is an amenable number.

7991216609 is a deficient number, since it is larger than the sum of its proper divisors (1).

7991216609 is an equidigital number, since it uses as much as digits as its factorization.

7991216609 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 367416, while the sum is 50.

The square root of 7991216609 is about 89393.6049670221. The cubic root of 7991216609 is about 1999.2677827116.

The spelling of 7991216609 in words is "seven billion, nine hundred ninety-one million, two hundred sixteen thousand, six hundred nine".