21101211200 has 84 divisors (see below), whose sum is σ = 51977045652. Its totient is φ = 8431564800.

The previous prime is 21101211193. The next prime is 21101211221. The reversal of 21101211200 is 211210112.

It can be written as a sum of positive squares in 6 ways, for example, as 124902976 + 20976308224 = 11176^2 + 144832^2 .

It is a super-2 number, since 2×21101211200² (a number of 21 digits) contains 22 as substring.

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, 1627142 + ... + 1640058.

It is an arithmetic number, because the mean of its divisors is an integer number (618774353).

Almost surely, 2^21101211200 is an apocalyptic number.

21101211200 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 21101211200, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (25988522826).

21101211200 is an abundant number, since it is smaller than the sum of its proper divisors (30875834452).

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

21101211200 is a wasteful number, since it uses less digits than its factorization.

21101211200 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 13960 (or 13945 counting only the distinct ones).

The product of its (nonzero) digits is 8, while the sum is 11.

Adding to 21101211200 its reverse (211210112), we get a palindrome (21312421312).

The spelling of 21101211200 in words is "twenty-one billion, one hundred one million, two hundred eleven thousand, two hundred".