200991 has 16 divisors (see below), whose sum is σ = 324864. Its totient is φ = 107904.

The previous prime is 200989. The next prime is 201007. The reversal of 200991 is 199002.

It is a happy number.

200991 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is not a de Polignac number, because 200991 - 2¹ = 200989 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (21).

200991 is a lucky number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (200971) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 76 + ... + 638.

It is an arithmetic number, because the mean of its divisors is an integer number (20304).

2²⁰⁰⁹⁹¹ is an apocalyptic number.

200991 is a gapful number since it is divisible by the number (21) formed by its first and last digit.

200991 is a deficient number, since it is larger than the sum of its proper divisors (123873).

200991 is a wasteful number, since it uses less digits than its factorization.

200991 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 590.

The product of its (nonzero) digits is 162, while the sum is 21.

The square root of 200991 is about 448.3201980728. The cubic root of 200991 is about 58.5767857200.

Adding to 200991 its reverse (199002), we get a palindrome (399993).

It can be divided in two parts, 20099 and 1, that added together give a triangular number (20100 = T₂₀₀).

The spelling of 200991 in words is "two hundred thousand, nine hundred ninety-one".