21211221001200 has 60 divisors (see below), whose sum is σ = 67946611277688. Its totient is φ = 5656325600000.

The previous prime is 21211221001199. The next prime is 21211221001297. The reversal of 21211221001200 is 210012211212.

It is a tau number, because it is divible by the number of its divisors (60).

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 21211221001200.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 8838007551 + ... + 8838009950.

Almost surely, 2^{21211221001200} is an apocalyptic number.

21211221001200 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21211221001200 is an abundant number, since it is smaller than the sum of its proper divisors (46735390276488).

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

21211221001200 is a wasteful number, since it uses less digits than its factorization.

21211221001200 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 17676017522 (or 17676017511 counting only the distinct ones).

The product of its (nonzero) digits is 32, while the sum is 15.

Adding to 21211221001200 its reverse (210012211212), we get a palindrome (21421233212412).

The spelling of 21211221001200 in words is "twenty-one trillion, two hundred eleven billion, two hundred twenty-one million, one thousand, two hundred".