21460 has 24 divisors (see below), whose sum is σ = 47880. Its totient is φ = 8064.

The previous prime is 21433. The next prime is 21467. The reversal of 21460 is 6412.

It can be written as a sum of positive squares in 4 ways, for example, as 6084 + 15376 = 78^2 + 124^2 .

It is a self number, because there is not a number n which added to its sum of digits gives 21460.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21467) 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, 562 + ... + 598.

It is an arithmetic number, because the mean of its divisors is an integer number (1995).

2²¹⁴⁶⁰ is an apocalyptic number.

21460 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 21460, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (23940).

21460 is an abundant number, since it is smaller than the sum of its proper divisors (26420).

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

21460 is a wasteful number, since it uses less digits than its factorization.

21460 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 75 (or 73 counting only the distinct ones).

The product of its (nonzero) digits is 48, while the sum is 13.

The square root of 21460 is about 146.4923206178. The cubic root of 21460 is about 27.7892337932.

Subtracting from 21460 its product of nonzero digits (48), we obtain a palindrome (21412).

Adding to 21460 its reverse (6412), we get a palindrome (27872).

The spelling of 21460 in words is "twenty-one thousand, four hundred sixty".