205851 has 8 divisors (see below), whose sum is σ = 279360. Its totient is φ = 134792.

The previous prime is 205847. The next prime is 205879. The reversal of 205851 is 158502.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 205851 - 2² = 205847 is a prime.

205851 is a lucky number.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 205851.

It is not an unprimeable number, because it can be changed into a prime (205151) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 405 + ... + 758.

It is an arithmetic number, because the mean of its divisors is an integer number (34920).

2²⁰⁵⁸⁵¹ is an apocalyptic number.

205851 is a deficient number, since it is larger than the sum of its proper divisors (73509).

205851 is a wasteful number, since it uses less digits than its factorization.

205851 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1225.

The product of its (nonzero) digits is 400, while the sum is 21.

The square root of 205851 is about 453.7080559126. The cubic root of 205851 is about 59.0451631599.

The spelling of 205851 in words is "two hundred five thousand, eight hundred fifty-one".