221100100 has 72 divisors (see below), whose sum is σ = 526606920. Its totient is φ = 80071680.

The previous prime is 221100059. The next prime is 221100101. The reversal of 221100100 is 1001122.

It can be written as a sum of positive squares in 12 ways, for example, as 67141636 + 153958464 = 8194^2 + 12408^2 .

It is not an unprimeable number, because it can be changed into a prime (221100101) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 67296 + ... + 70504.

It is an arithmetic number, because the mean of its divisors is an integer number (7313985).

Almost surely, 2^221100100 is an apocalyptic number.

221100100 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 221100100, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (263303460).

221100100 is an abundant number, since it is smaller than the sum of its proper divisors (305506820).

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

221100100 is a wasteful number, since it uses less digits than its factorization.

221100100 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3289 (or 3282 counting only the distinct ones).

The product of its (nonzero) digits is 4, while the sum is 7.

The square root of 221100100 is about 14869.4350935064. The cubic root of 221100100 is about 604.6856277165.

Adding to 221100100 its reverse (1001122), we get a palindrome (222101222).

The spelling of 221100100 in words is "two hundred twenty-one million, one hundred thousand, one hundred".