199997797 has 2 divisors, whose sum is σ = 199997798. Its totient is φ = 199997796.

The previous prime is 199997767. The next prime is 199997851. The reversal of 199997797 is 797799991.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 198218241 + 1779556 = 14079^2 + 1334^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-199997797 is a prime.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (199997767) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 99998898 + 99998899.

It is an arithmetic number, because the mean of its divisors is an integer number (99998899).

Almost surely, 2^199997797 is an apocalyptic number.

It is an amenable number.

199997797 is a deficient number, since it is larger than the sum of its proper divisors (1).

199997797 is an equidigital number, since it uses as much as digits as its factorization.

199997797 is an evil number, because the sum of its binary digits is even.

The product of its digits is 20253807, while the sum is 67.

The square root of 199997797 is about 14142.0577357045. The cubic root of 199997797 is about 584.8014004310.

The spelling of 199997797 in words is "one hundred ninety-nine million, nine hundred ninety-seven thousand, seven hundred ninety-seven".