199851 has 4 divisors (see below), whose sum is σ = 266472. Its totient is φ = 133232.

The previous prime is 199831. The next prime is 199853. The reversal of 199851 is 158991.

199851 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 199851 - 2⁵ = 199819 is a prime.

It is a D-number.

199851 is a lucky number.

It is not an unprimeable number, because it can be changed into a prime (199853) 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, 33306 + ... + 33311.

It is an arithmetic number, because the mean of its divisors is an integer number (66618).

2¹⁹⁹⁸⁵¹ is an apocalyptic number.

199851 is a deficient number, since it is larger than the sum of its proper divisors (66621).

199851 is an equidigital number, since it uses as much as digits as its factorization.

199851 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 66620.

The product of its digits is 3240, while the sum is 33.

The square root of 199851 is about 447.0469773972. The cubic root of 199851 is about 58.4658285349.

It can be divided in two parts, 19 and 9851, that added together give a triangular number (9870 = T₁₄₀).

The spelling of 199851 in words is "one hundred ninety-nine thousand, eight hundred fifty-one".