21211121200 has 120 divisors (see below), whose sum is σ = 53822457920. Its totient is φ = 8010835200.

The previous prime is 21211121189. The next prime is 21211121207. The reversal of 21211121200 is 212111212.

It is a super-2 number, since 2×21211121200² (a number of 21 digits) contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (21211121207) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 2328655 + ... + 2337745.

Almost surely, 2^21211121200 is an apocalyptic number.

21211121200 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 21211121200, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (26911228960).

21211121200 is an abundant number, since it is smaller than the sum of its proper divisors (32611336720).

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

21211121200 is a wasteful number, since it uses less digits than its factorization.

21211121200 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9435 (or 9424 counting only the distinct ones).

The product of its (nonzero) digits is 16, while the sum is 13.

Adding to 21211121200 its reverse (212111212), we get a palindrome (21423232412).

21211121200 divided by its reverse (212111212) gives a square (100 = 10²).

The spelling of 21211121200 in words is "twenty-one billion, two hundred eleven million, one hundred twenty-one thousand, two hundred".