20880 has 60 divisors (see below), whose sum is σ = 72540. Its totient is φ = 5376.

The previous prime is 20879. The next prime is 20887. The reversal of 20880 is 8802.

20880 is an esthetic number in base 14, because in such base its adjacent digits differ by 1.

It can be written as a sum of positive squares in 2 ways, for example, as 9216 + 11664 = 96^2 + 108^2 .

It is a tau number, because it is divible by the number of its divisors (60).

It is a Harshad number since it is a multiple of its sum of digits (18).

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

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20887) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (5) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 706 + ... + 734.

It is an arithmetic number, because the mean of its divisors is an integer number (1209).

2²⁰⁸⁸⁰ is an apocalyptic number.

20880 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is a pronic number, being equal to 144×145.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 20880, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (36270).

20880 is an abundant number, since it is smaller than the sum of its proper divisors (51660).

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

20880 is a wasteful number, since it uses less digits than its factorization.

20880 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 48 (or 39 counting only the distinct ones).

The product of its (nonzero) digits is 128, while the sum is 18.

The square root of 20880 is about 144.4991349455. The cubic root of 20880 is about 27.5365904111.

It can be divided in two parts, 20 and 880, that added together give a square (900 = 30²).

The spelling of 20880 in words is "twenty thousand, eight hundred eighty".