21213200 has 60 divisors (see below), whose sum is σ = 51421188. Its totient is φ = 8409600.

The previous prime is 21213193. The next prime is 21213251. The reversal of 21213200 is 231212.

It is a happy number.

It can be written as a sum of positive squares in 6 ways, for example, as 891136 + 20322064 = 944^2 + 4508^2 .

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 72254 + ... + 72546.

Almost surely, 2^21213200 is an apocalyptic number.

21213200 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 21213200, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (25710594).

21213200 is an abundant number, since it is smaller than the sum of its proper divisors (30207988).

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

21213200 is a wasteful number, since it uses less digits than its factorization.

21213200 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 492 (or 481 counting only the distinct ones).

The product of its (nonzero) digits is 24, while the sum is 11.

The square root of 21213200 is about 4605.7789786311. The cubic root of 21213200 is about 276.8229307075.

Adding to 21213200 its reverse (231212), we get a palindrome (21444412).

The spelling of 21213200 in words is "twenty-one million, two hundred thirteen thousand, two hundred".