It is a plaindrome in base 15.
It is a congruent number.
It is an unprimeable number.
2221368 is an apocalyptic number.
221368 is a gapful number since it is divisible by the number (28) 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 221368, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (244800).
It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.
221368 is a wasteful number, since it uses less digits than its factorization.
221368 is an evil number, because the sum of its binary digits is even.
The square root of 221368 is about 470.4976089206. The cubic root of 221368 is about 60.4929755294.
The spelling of 221368 in words is "two hundred twenty-one thousand, three hundred sixty-eight".