221211221100 has 144 divisors (see below), whose sum is σ = 650911672320. Its totient is φ = 57992716800.

The previous prime is 221211221051. The next prime is 221211221201. The reversal of 221211221100 is 1122112122.

221211221100 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a Harshad number since it is a multiple of its sum of digits (15).

It is a self number, because there is not a number n which added to its sum of digits gives 221211221100.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 6794661 + ... + 6827139.

Almost surely, 2^221211221100 is an apocalyptic number.

221211221100 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 221211221100, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (325455836160).

221211221100 is an abundant number, since it is smaller than the sum of its proper divisors (429700451220).

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

221211221100 is a wasteful number, since it uses less digits than its factorization.

221211221100 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 32880 (or 32873 counting only the distinct ones).

The product of its (nonzero) digits is 32, while the sum is 15.

Adding to 221211221100 its reverse (1122112122), we get a palindrome (222333333222).

The spelling of 221211221100 in words is "two hundred twenty-one billion, two hundred eleven million, two hundred twenty-one thousand, one hundred".