20280 has 48 divisors (see below), whose sum is σ = 65880. Its totient is φ = 4992.

The previous prime is 20269. The next prime is 20287. The reversal of 20280 is 8202.

It is a super-2 number, since 2×20280² = 822556800, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (12).

It is a super Niven number, because it is divisible the sum of any subset of its (nonzero) digits.

It is a nialpdrome in base 13.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20287) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 1554 + ... + 1566.

2²⁰²⁸⁰ is an apocalyptic number.

20280 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 20280, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (32940).

20280 is an abundant number, since it is smaller than the sum of its proper divisors (45600).

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

20280 is a wasteful number, since it uses less digits than its factorization.

20280 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 40 (or 23 counting only the distinct ones).

The product of its (nonzero) digits is 32, while the sum is 12.

The square root of 20280 is about 142.4078649513. The cubic root of 20280 is about 27.2702624035.

Adding to 20280 its reverse (8202), we get a palindrome (28482).

It can be divided in two parts, 202 and 80, that added together give a palindrome (282).

The spelling of 20280 in words is "twenty thousand, two hundred eighty".