20490 has 16 divisors (see below), whose sum is σ = 49248. Its totient is φ = 5456.

The previous prime is 20483. The next prime is 20507. The reversal of 20490 is 9402.

20490 = 62² + 63² + ... + 66².

20490 is digitally balanced in base 6, because in such base it contains all the possibile digits an equal number of times.

20490 is an esthetic number in base 14, because in such base its adjacent digits differ by 1.

It is a Harshad number since it is a multiple of its sum of digits (15).

20490 is strictly pandigital in base 6.

It is a nialpdrome in base 13 and base 15.

It is a zygodrome in base 4.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 20490.

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, 312 + ... + 371.

It is an arithmetic number, because the mean of its divisors is an integer number (3078).

2²⁰⁴⁹⁰ is an apocalyptic number.

20490 is an abundant number, since it is smaller than the sum of its proper divisors (28758).

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 (24624).

20490 is a wasteful number, since it uses less digits than its factorization.

20490 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 693.

The product of its (nonzero) digits is 72, while the sum is 15.

The square root of 20490 is about 143.1432848582. The cubic root of 20490 is about 27.3640674846.

Adding to 20490 its reverse (9402), we get a palindrome (29892).

The spelling of 20490 in words is "twenty thousand, four hundred ninety".