205490 has 8 divisors (see below), whose sum is σ = 369900. Its totient is φ = 82192.

The previous prime is 205487. The next prime is 205493. The reversal of 205490 is 94502.

It is an interprime number because it is at equal distance from previous prime (205487) and next prime (205493).

It can be written as a sum of positive squares in 2 ways, for example, as 192721 + 12769 = 439^2 + 113^2 .

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

It is a super-2 number, since 2×205490² = 84452280200, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (205493) 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, 10265 + ... + 10284.

2²⁰⁵⁴⁹⁰ is an apocalyptic number.

205490 is a deficient number, since it is larger than the sum of its proper divisors (164410).

205490 is a wasteful number, since it uses less digits than its factorization.

205490 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 20556.

The product of its (nonzero) digits is 360, while the sum is 20.

The square root of 205490 is about 453.3100484216. The cubic root of 205490 is about 59.0106272152.

Adding to 205490 its reverse (94502), we get a palindrome (299992).

The spelling of 205490 in words is "two hundred five thousand, four hundred ninety".