21220021200 has 240 divisors, whose sum is σ = 78960926336. Its totient is φ = 4770662400.

The previous prime is 21220021157. The next prime is 21220021223. The reversal of 21220021200 is 212002212.

It is a tau number, because it is divible by the number of its divisors (240).

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 (19) of ones.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 491694 + ... + 533106.

Almost surely, 2^21220021200 is an apocalyptic number.

21220021200 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 21220021200, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (39480463168).

21220021200 is an abundant number, since it is smaller than the sum of its proper divisors (57740905136).

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

21220021200 is a wasteful number, since it uses less digits than its factorization.

21220021200 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 41502 (or 41491 counting only the distinct ones).

The product of its (nonzero) digits is 32, while the sum is 12.

Adding to 21220021200 its reverse (212002212), we get a palindrome (21432023412).

The spelling of 21220021200 in words is "twenty-one billion, two hundred twenty million, twenty-one thousand, two hundred".