21211211200 has 42 divisors (see below), whose sum is σ = 52192840496. Its totient is φ = 8484483840.

The previous prime is 21211211191. The next prime is 21211211207. The reversal of 21211211200 is 211211212.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21211211207) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 6626904 + ... + 6630103.

Almost surely, 2^21211211200 is an apocalyptic number.

21211211200 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21211211200 is an abundant number, since it is smaller than the sum of its proper divisors (30981629296).

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

21211211200 is a wasteful number, since it uses less digits than its factorization.

21211211200 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 13257029 (or 13257014 counting only the distinct ones).

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

Adding to 21211211200 its reverse (211211212), we get a palindrome (21422422412).

The spelling of 21211211200 in words is "twenty-one billion, two hundred eleven million, two hundred eleven thousand, two hundred".