21021224200 has 144 divisors (see below), whose sum is σ = 53712996300. Its totient is φ = 7640371200.

The previous prime is 21021224179. The next prime is 21021224209. The reversal of 21021224200 is 242212012.

It can be written as a sum of positive squares in 18 ways, for example, as 2745969604 + 18275254596 = 52402^2 + 135186^2 .

It is not an unprimeable number, because it can be changed into a prime (21021224209) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 35 ways as a sum of consecutive naturals, for example, 1669930 + ... + 1682470.

Almost surely, 2^21021224200 is an apocalyptic number.

21021224200 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 21021224200, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (26856498150).

21021224200 is an abundant number, since it is smaller than the sum of its proper divisors (32691772100).

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

21021224200 is a wasteful number, since it uses less digits than its factorization.

21021224200 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 12620 (or 12594 counting only the distinct ones).

The product of its (nonzero) digits is 128, while the sum is 16.

Adding to 21021224200 its reverse (242212012), we get a palindrome (21263436212).

The spelling of 21021224200 in words is "twenty-one billion, twenty-one million, two hundred twenty-four thousand, two hundred".