21000212221200 has 120 divisors (see below), whose sum is σ = 68835114398688. Its totient is φ = 5469822704640.

The previous prime is 21000212221193. The next prime is 21000212221207. The reversal of 21000212221200 is 212221200012.

It is an interprime number because it is at equal distance from previous prime (21000212221193) and next prime (21000212221207).

It is a tau number, because it is divible by the number of its divisors (120).

It is a Harshad number since it is a multiple of its sum of digits (15).

It is a self number, because there is not a number n which added to its sum of digits gives 21000212221200.

It is not an unprimeable number, because it can be changed into a prime (21000212221207) by changing a digit.

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 23 ways as a sum of consecutive naturals, for example, 203438829 + ... + 203542028.

Almost surely, 2^{21000212221200} is an apocalyptic number.

21000212221200 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21000212221200 is an abundant number, since it is smaller than the sum of its proper divisors (47834902177488).

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

21000212221200 is a wasteful number, since it uses less digits than its factorization.

21000212221200 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 406980921 (or 406980910 counting only the distinct ones).

The product of its (nonzero) digits is 64, while the sum is 15.

Adding to 21000212221200 its reverse (212221200012), we get a palindrome (21212433421212).

The spelling of 21000212221200 in words is "twenty-one trillion, two hundred twelve million, two hundred twenty-one thousand, two hundred".