205690 has 16 divisors (see below), whose sum is σ = 376992. Its totient is φ = 80784.

The previous prime is 205663. The next prime is 205703. The reversal of 205690 is 96502.

It is a super-2 number, since 2×205690² = 84616752200, which contains 22 as substring.

It is an Ulam number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 517 + ... + 823.

It is an arithmetic number, because the mean of its divisors is an integer number (23562).

2²⁰⁵⁶⁹⁰ is an apocalyptic number.

205690 is a deficient number, since it is larger than the sum of its proper divisors (171302).

205690 is a wasteful number, since it uses less digits than its factorization.

205690 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 381.

The product of its (nonzero) digits is 540, while the sum is 22.

The square root of 205690 is about 453.5305943374. The cubic root of 205690 is about 59.0297656949.

The spelling of 205690 in words is "two hundred five thousand, six hundred ninety".