20290 has 8 divisors (see below), whose sum is σ = 36540. Its totient is φ = 8112.

The previous prime is 20287. The next prime is 20297. The reversal of 20290 is 9202.

It can be written as a sum of positive squares in 2 ways, for example, as 18769 + 1521 = 137^2 + 39^2 .

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

It is a self number, because there is not a number n which added to its sum of digits gives 20290.

It is not an unprimeable number, because it can be changed into a prime (20297) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1005 + ... + 1024.

2²⁰²⁹⁰ is an apocalyptic number.

20290 is a deficient number, since it is larger than the sum of its proper divisors (16250).

20290 is a wasteful number, since it uses less digits than its factorization.

20290 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2036.

The product of its (nonzero) digits is 36, while the sum is 13.

The square root of 20290 is about 142.4429710446. The cubic root of 20290 is about 27.2747439586.

Adding to 20290 its reverse (9202), we get a palindrome (29492).

It can be divided in two parts, 202 and 90, that added together give a palindrome (292).

The spelling of 20290 in words is "twenty thousand, two hundred ninety".