20090 has 24 divisors (see below), whose sum is σ = 43092. Its totient is φ = 6720.

The previous prime is 20089. The next prime is 20101. The reversal of 20090 is 9002.

It can be written as a sum of positive squares in 2 ways, for example, as 17689 + 2401 = 133^2 + 49^2 .

20090 is a modest number, since divided by 90 gives 20 as remainder.

It is a nialpdrome in base 12.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 470 + ... + 510.

2²⁰⁰⁹⁰ is an apocalyptic number.

20090 is an abundant number, since it is smaller than the sum of its proper divisors (23002).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

It is a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (21546).

20090 is a wasteful number, since it uses less digits than its factorization.

20090 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 62 (or 55 counting only the distinct ones).

The product of its (nonzero) digits is 18, while the sum is 11.

The square root of 20090 is about 141.7391971192. The cubic root of 20090 is about 27.1848315080.

Adding to 20090 its reverse (9002), we get a palindrome (29092).

The spelling of 20090 in words is "twenty thousand, ninety".