199685 has 4 divisors (see below), whose sum is σ = 239628. Its totient is φ = 159744.

The previous prime is 199679. The next prime is 199687. The reversal of 199685 is 586991.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 586991 = 59 ⋅9949.

It can be written as a sum of positive squares in 2 ways, for example, as 124609 + 75076 = 353^2 + 274^2 .

It is a cyclic number.

It is not a de Polignac number, because 199685 - 2⁴ = 199669 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (199687) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 19964 + ... + 19973.

It is an arithmetic number, because the mean of its divisors is an integer number (59907).

2¹⁹⁹⁶⁸⁵ is an apocalyptic number.

It is an amenable number.

199685 is a deficient number, since it is larger than the sum of its proper divisors (39943).

199685 is an equidigital number, since it uses as much as digits as its factorization.

199685 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 39942.

The product of its digits is 19440, while the sum is 38.

The square root of 199685 is about 446.8612760130. The cubic root of 199685 is about 58.4496364452.

The spelling of 199685 in words is "one hundred ninety-nine thousand, six hundred eighty-five".