21213300 has 72 divisors (see below), whose sum is σ = 63384832. Its totient is φ = 5472000.

The previous prime is 21213293. The next prime is 21213341. The reversal of 21213300 is 331212.

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 an unprimeable number.

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 23 ways as a sum of consecutive naturals, for example, 8160 + ... + 10440.

Almost surely, 2^21213300 is an apocalyptic number.

21213300 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 21213300, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (31692416).

21213300 is an abundant number, since it is smaller than the sum of its proper divisors (42171532).

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

21213300 is a wasteful number, since it uses less digits than its factorization.

21213300 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2329 (or 2322 counting only the distinct ones).

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

The square root of 21213300 is about 4605.7898345452. The cubic root of 21213300 is about 276.8233656921.

Adding to 21213300 its reverse (331212), we get a palindrome (21544512).

The spelling of 21213300 in words is "twenty-one million, two hundred thirteen thousand, three hundred".