211221210100 has 144 divisors (see below), whose sum is σ = 472119782400. Its totient is φ = 81985115520.

The previous prime is 211221210077. The next prime is 211221210121. The reversal of 211221210100 is 1012122112.

It is a super-2 number, since 2×211221210100² (a number of 23 digits) contains 22 as substring.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 504107691 + ... + 504108109.

It is an arithmetic number, because the mean of its divisors is an integer number (3278609600).

Almost surely, 2^211221210100 is an apocalyptic number.

211221210100 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 211221210100, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (236059891200).

211221210100 is an abundant number, since it is smaller than the sum of its proper divisors (260898572300).

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

211221210100 is a wasteful number, since it uses less digits than its factorization.

211221210100 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1142 (or 1135 counting only the distinct ones).

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

Adding to 211221210100 its reverse (1012122112), we get a palindrome (212233332212).

The spelling of 211221210100 in words is "two hundred eleven billion, two hundred twenty-one million, two hundred ten thousand, one hundred".