21211101200 has 120 divisors (see below), whose sum is σ = 51841875360. Its totient is φ = 8338176000.

The previous prime is 21211101199. The next prime is 21211101209. The reversal of 21211101200 is 210111212.

It is not an unprimeable number, because it can be changed into a prime (21211101209) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 17660600 + ... + 17661800.

It is an arithmetic number, because the mean of its divisors is an integer number (432015628).

Almost surely, 2^21211101200 is an apocalyptic number.

21211101200 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 21211101200, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (25920937680).

21211101200 is an abundant number, since it is smaller than the sum of its proper divisors (30630774160).

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

21211101200 is a wasteful number, since it uses less digits than its factorization.

21211101200 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1945 (or 1934 counting only the distinct ones).

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

Adding to 21211101200 its reverse (210111212), we get a palindrome (21421212412).

The spelling of 21211101200 in words is "twenty-one billion, two hundred eleven million, one hundred one thousand, two hundred".