21211300 has 54 divisors (see below), whose sum is σ = 50622194. Its totient is φ = 7708800.

The previous prime is 21211259. The next prime is 21211319. The reversal of 21211300 is 311212.

It can be written as a sum of positive squares in 3 ways, for example, as 69696 + 21141604 = 264^2 + 4598^2 .

It is a Harshad number since it is a multiple of its sum of digits (10).

It is an unprimeable number.

It is a polite number, since it can be written in 17 ways as a sum of consecutive naturals, for example, 11224 + ... + 12976.

Almost surely, 2^21211300 is an apocalyptic number.

21211300 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 21211300, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (25311097).

21211300 is an abundant number, since it is smaller than the sum of its proper divisors (29410894).

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

21211300 is a wasteful number, since it uses less digits than its factorization.

21211300 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1789 (or 1771 counting only the distinct ones).

The product of its (nonzero) digits is 12, while the sum is 10.

The square root of 21211300 is about 4605.5727114008. The cubic root of 21211300 is about 276.8146657393.

Adding to 21211300 its reverse (311212), we get a palindrome (21522512).

The spelling of 21211300 in words is "twenty-one million, two hundred eleven thousand, three hundred".