16591997797 has 2 divisors, whose sum is σ = 16591997798. Its totient is φ = 16591997796.

The previous prime is 16591997791. The next prime is 16591997813. The reversal of 16591997797 is 79779919561.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 16560086596 + 31911201 = 128686^2 + 5649^2 .

It is a cyclic number.

It is not a de Polignac number, because 16591997797 - 2¹⁵ = 16591965029 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (16591997791) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 8295998898 + 8295998899.

It is an arithmetic number, because the mean of its divisors is an integer number (8295998899).

Almost surely, 2^16591997797 is an apocalyptic number.

It is an amenable number.

16591997797 is a deficient number, since it is larger than the sum of its proper divisors (1).

16591997797 is an equidigital number, since it uses as much as digits as its factorization.

16591997797 is an evil number, because the sum of its binary digits is even.

The product of its digits is 67512690, while the sum is 70.

The spelling of 16591997797 in words is "sixteen billion, five hundred ninety-one million, nine hundred ninety-seven thousand, seven hundred ninety-seven".