221111100 has 144 divisors (see below), whose sum is σ = 812448000. Its totient is φ = 50535360.

The previous prime is 221111063. The next prime is 221111123. The reversal of 221111100 is 1111122.

It is a happy number.

It is a Harshad number since it is a multiple of its sum of digits (9).

It is a nialpdrome in base 10.

It is a zygodrome in base 10.

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, 13051 + ... + 24749.

It is an arithmetic number, because the mean of its divisors is an integer number (5642000).

Almost surely, 2^221111100 is an apocalyptic number.

221111100 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 221111100, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (406224000).

221111100 is an abundant number, since it is smaller than the sum of its proper divisors (591336900).

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

221111100 is a wasteful number, since it uses less digits than its factorization.

221111100 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 11729 (or 11716 counting only the distinct ones).

The product of its (nonzero) digits is 4, while the sum is 9.

The square root of 221111100 is about 14869.8049751838. The cubic root of 221111100 is about 604.6956554996.

Adding to 221111100 its reverse (1111122), we get a palindrome (222222222).

The spelling of 221111100 in words is "two hundred twenty-one million, one hundred eleven thousand, one hundred".