21221303200 has 72 divisors (see below), whose sum is σ = 52021943820. Its totient is φ = 8453222400.

The previous prime is 21221303153. The next prime is 21221303209. The reversal of 21221303200 is 230312212.

It can be written as a sum of positive squares in 6 ways, for example, as 11563131024 + 9658172176 = 107532^2 + 98276^2 .

It is a Harshad number since it is a multiple of its sum of digits (16).

It is not an unprimeable number, because it can be changed into a prime (21221303209) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 137766 + ... + 247834.

Almost surely, 2^21221303200 is an apocalyptic number.

21221303200 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 21221303200, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (26010971910).

21221303200 is an abundant number, since it is smaller than the sum of its proper divisors (30800640620).

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

21221303200 is a wasteful number, since it uses less digits than its factorization.

21221303200 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 110330 (or 110317 counting only the distinct ones).

The product of its (nonzero) digits is 144, while the sum is 16.

Adding to 21221303200 its reverse (230312212), we get a palindrome (21451615412).

The spelling of 21221303200 in words is "twenty-one billion, two hundred twenty-one million, three hundred three thousand, two hundred".