21480 has 32 divisors (see below), whose sum is σ = 64800. Its totient is φ = 5696.

The previous prime is 21467. The next prime is 21481. The reversal of 21480 is 8412.

21480 is digitally balanced in base 4, because in such base it contains all the possibile digits an equal number of times.

It is a super-2 number, since 2×21480² = 922780800, which contains 22 as substring.

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

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 21480.

It is not an unprimeable number, because it can be changed into a prime (21481) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 31 + ... + 209.

It is an arithmetic number, because the mean of its divisors is an integer number (2025).

2²¹⁴⁸⁰ is an apocalyptic number.

21480 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 21480, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (32400).

21480 is an abundant number, since it is smaller than the sum of its proper divisors (43320).

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

21480 is a wasteful number, since it uses less digits than its factorization.

21480 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 193 (or 189 counting only the distinct ones).

The product of its (nonzero) digits is 64, while the sum is 15.

The square root of 21480 is about 146.5605676845. The cubic root of 21480 is about 27.7978639906.

Adding to 21480 its reverse (8412), we get a palindrome (29892).

The spelling of 21480 in words is "twenty-one thousand, four hundred eighty".