21321300 has 288 divisors, whose sum is σ = 83994624. Its totient is φ = 4032000.

The previous prime is 21321283. The next prime is 21321301. The reversal of 21321300 is 312312.

It is a happy number.

It is a Harshad number since it is a multiple of its sum of digits (12).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21321301) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 95 ways as a sum of consecutive naturals, for example, 300265 + ... + 300335.

It is an arithmetic number, because the mean of its divisors is an integer number (291648).

Almost surely, 2^21321300 is an apocalyptic number.

21321300 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 21321300, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (41997312).

21321300 is an abundant number, since it is smaller than the sum of its proper divisors (62673324).

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

21321300 is a wasteful number, since it uses less digits than its factorization.

21321300 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 119 (or 112 counting only the distinct ones).

The product of its (nonzero) digits is 36, while the sum is 12.

The square root of 21321300 is about 4617.4993232268. The cubic root of 21321300 is about 277.2923533867.

Adding to 21321300 its reverse (312312), we get a palindrome (21633612).

It can be divided in two parts, 213 and 21300, that multiplied together give a square (4536900 = 2130²).

The spelling of 21321300 in words is "twenty-one million, three hundred twenty-one thousand, three hundred".