199718657 has 2 divisors, whose sum is σ = 199718658. Its totient is φ = 199718656.

The previous prime is 199718641. The next prime is 199718663. The reversal of 199718657 is 756817991.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 189227536 + 10491121 = 13756^2 + 3239^2 .

It is a cyclic number.

It is not a de Polignac number, because 199718657 - 2⁴ = 199718641 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 199718599 and 199718608.

It is not a weakly prime, because it can be changed into another prime (199718627) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 99859328 + 99859329.

It is an arithmetic number, because the mean of its divisors is an integer number (99859329).

Almost surely, 2^199718657 is an apocalyptic number.

It is an amenable number.

199718657 is a deficient number, since it is larger than the sum of its proper divisors (1).

199718657 is an equidigital number, since it uses as much as digits as its factorization.

199718657 is an evil number, because the sum of its binary digits is even.

The product of its digits is 952560, while the sum is 53.

The square root of 199718657 is about 14132.1851459709. The cubic root of 199718657 is about 584.5292016526.

The spelling of 199718657 in words is "one hundred ninety-nine million, seven hundred eighteen thousand, six hundred fifty-seven".