7991216687 has 2 divisors, whose sum is σ = 7991216688. Its totient is φ = 7991216686.

The previous prime is 7991216663. The next prime is 7991216693. The reversal of 7991216687 is 7866121997.

It is a strong prime.

It is an emirp because it is prime and its reverse (7866121997) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 7991216687 - 2¹⁰ = 7991215663 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (7991216617) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 3995608343 + 3995608344.

It is an arithmetic number, because the mean of its divisors is an integer number (3995608344).

Almost surely, 2^7991216687 is an apocalyptic number.

7991216687 is a deficient number, since it is larger than the sum of its proper divisors (1).

7991216687 is an equidigital number, since it uses as much as digits as its factorization.

7991216687 is an evil number, because the sum of its binary digits is even.

The product of its digits is 2286144, while the sum is 56.

The square root of 7991216687 is about 89393.6054032949. The cubic root of 7991216687 is about 1999.2677892164.

The spelling of 7991216687 in words is "seven billion, nine hundred ninety-one million, two hundred sixteen thousand, six hundred eighty-seven".