221100 has 72 divisors (see below), whose sum is σ = 708288. Its totient is φ = 52800.
The previous prime is 221093. The next prime is 221101. The reversal of 221100 is 1122.
It is a happy number.
It is a Harshad number since it is a multiple of its sum of digits (6).
It is a super Niven number, because it is divisible the sum of any subset of its (nonzero) digits.
It is a nialpdrome in base 10.
It is a zygodrome in base 10.
It is not an unprimeable number, because it can be changed into a prime (221101) by changing a digit.
221100 is an untouchable number, because it is not equal to the sum of proper divisors of any number.
It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 3267 + ... + 3333.
2221100 is an apocalyptic number.
221100 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 221100, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (354144).
221100 is an abundant number, since it is smaller than the sum of its proper divisors (487188).
It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.
221100 is a wasteful number, since it uses less digits than its factorization.
221100 is an evil number, because the sum of its binary digits is even.
The sum of its prime factors is 95 (or 88 counting only the distinct ones).
The product of its (nonzero) digits is 4, while the sum is 6.
The square root of 221100 is about 470.2127178203. The cubic root of 221100 is about 60.4685536553.
Adding to 221100 its reverse (1122), we get a palindrome (222222).
The spelling of 221100 in words is "two hundred twenty-one thousand, one hundred", and thus it is an iban number.
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