6991616497 has 2 divisors, whose sum is σ = 6991616498. Its totient is φ = 6991616496.

The previous prime is 6991616491. The next prime is 6991616551. The reversal of 6991616497 is 7946161996.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 6723836001 + 267780496 = 81999^2 + 16364^2 .

It is a cyclic number.

It is not a de Polignac number, because 6991616497 - 2⁷ = 6991616369 is a prime.

It is a super-2 number, since 2×6991616497² = 97765402482245102018, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (6991616491) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 3495808248 + 3495808249.

It is an arithmetic number, because the mean of its divisors is an integer number (3495808249).

Almost surely, 2^6991616497 is an apocalyptic number.

It is an amenable number.

6991616497 is a deficient number, since it is larger than the sum of its proper divisors (1).

6991616497 is an equidigital number, since it uses as much as digits as its factorization.

6991616497 is an evil number, because the sum of its binary digits is even.

The product of its digits is 4408992, while the sum is 58.

The square root of 6991616497 is about 83615.8866304723. The cubic root of 6991616497 is about 1912.1672079724.

The spelling of 6991616497 in words is "six billion, nine hundred ninety-one million, six hundred sixteen thousand, four hundred ninety-seven".