16605568691 has 2 divisors, whose sum is σ = 16605568692. Its totient is φ = 16605568690.

The previous prime is 16605568673. The next prime is 16605568709. The reversal of 16605568691 is 19686550661.

It is a balanced prime because it is at equal distance from previous prime (16605568673) and next prime (16605568709).

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-16605568691 is a prime.

It is not a weakly prime, because it can be changed into another prime (16605568891) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 8302784345 + 8302784346.

It is an arithmetic number, because the mean of its divisors is an integer number (8302784346).

Almost surely, 2^16605568691 is an apocalyptic number.

16605568691 is a deficient number, since it is larger than the sum of its proper divisors (1).

16605568691 is an equidigital number, since it uses as much as digits as its factorization.

16605568691 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 2332800, while the sum is 53.

The spelling of 16605568691 in words is "sixteen billion, six hundred five million, five hundred sixty-eight thousand, six hundred ninety-one".