21200 has 30 divisors (see below), whose sum is σ = 51894. Its totient is φ = 8320.

The previous prime is 21193. The next prime is 21211. The reversal of 21200 is 212.

It can be written as a sum of positive squares in 3 ways, for example, as 2704 + 18496 = 52^2 + 136^2 .

It is a Harshad number since it is a multiple of its sum of digits (5).

It is a zygodrome in base 7.

It is a congruent number.

It is an unprimeable number.

21200 is an untouchable number, because it is not equal to the sum of proper divisors of any number.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 374 + ... + 426.

2²¹²⁰⁰ is an apocalyptic number.

21200 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 21200, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (25947).

21200 is an abundant number, since it is smaller than the sum of its proper divisors (30694).

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

21200 is a wasteful number, since it uses less digits than its factorization.

21200 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 71 (or 60 counting only the distinct ones).

The product of its (nonzero) digits is 4, while the sum is 5.

The square root of 21200 is about 145.6021977856. The cubic root of 21200 is about 27.6765500729.

Adding to 21200 its reverse (212), we get a palindrome (21412).

Multiplying 21200 by its reverse (212), we get a square (4494400 = 2120²).

21200 divided by its reverse (212) gives a square (100 = 10²).

The spelling of 21200 in words is "twenty-one thousand, two hundred", and thus it is an iban number.