199851697 has 2 divisors, whose sum is σ = 199851698. Its totient is φ = 199851696.

The previous prime is 199851679. The next prime is 199851721. The reversal of 199851697 is 796158991.

Together with previous prime (199851679) it forms an Ormiston pair, because they use the same digits, order apart.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 162409536 + 37442161 = 12744^2 + 6119^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-199851697 is a prime.

It is not a weakly prime, because it can be changed into another prime (199851607) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 99925848 + 99925849.

It is an arithmetic number, because the mean of its divisors is an integer number (99925849).

Almost surely, 2^199851697 is an apocalyptic number.

It is an amenable number.

199851697 is a deficient number, since it is larger than the sum of its proper divisors (1).

199851697 is an equidigital number, since it uses as much as digits as its factorization.

199851697 is an evil number, because the sum of its binary digits is even.

The product of its digits is 1224720, while the sum is 55.

The square root of 199851697 is about 14136.8913485250. The cubic root of 199851697 is about 584.6589650324.

The spelling of 199851697 in words is "one hundred ninety-nine million, eight hundred fifty-one thousand, six hundred ninety-seven".