221200100 has 108 divisors (see below), whose sum is σ = 535775604. Its totient is φ = 79200000.

The previous prime is 221200093. The next prime is 221200121. The reversal of 221200100 is 1002122.

It can be written as a sum of positive squares in 6 ways, for example, as 7806436 + 213393664 = 2794^2 + 14608^2 .

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 35 ways as a sum of consecutive naturals, for example, 1222010 + ... + 1222190.

Almost surely, 2^221200100 is an apocalyptic number.

221200100 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 221200100, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (267887802).

221200100 is an abundant number, since it is smaller than the sum of its proper divisors (314575504).

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

221200100 is a wasteful number, since it uses less digits than its factorization.

221200100 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 318 (or 300 counting only the distinct ones).

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

The square root of 221200100 is about 14872.7973159053. The cubic root of 221200100 is about 604.7767771532.

Adding to 221200100 its reverse (1002122), we get a palindrome (222202222).

The spelling of 221200100 in words is "two hundred twenty-one million, two hundred thousand, one hundred".