199977797 has 2 divisors, whose sum is σ = 199977798. Its totient is φ = 199977796.

The previous prime is 199977779. The next prime is 199977803. The reversal of 199977797 is 797779991.

Together with previous prime (199977779) it forms an Ormiston pair, because they use the same digits, order apart.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 199120321 + 857476 = 14111^2 + 926^2 .

It is an emirp because it is prime and its reverse (797779991) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 199977797 - 2¹⁰ = 199976773 is a prime.

It is a super-2 number, since 2×199977797² = 79982238585946418, which contains 22 as substring.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (199977737) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 99988898 + 99988899.

It is an arithmetic number, because the mean of its divisors is an integer number (99988899).

Almost surely, 2^199977797 is an apocalyptic number.

It is an amenable number.

199977797 is a deficient number, since it is larger than the sum of its proper divisors (1).

199977797 is an equidigital number, since it uses as much as digits as its factorization.

199977797 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 15752961, while the sum is 65.

The square root of 199977797 is about 14141.3506073501. The cubic root of 199977797 is about 584.7819061864.

The spelling of 199977797 in words is "one hundred ninety-nine million, nine hundred seventy-seven thousand, seven hundred ninety-seven".