It is a happy number.
It is a self number, because there is not a number n which added to its sum of digits gives 22221780.
It is a congruent number.
Almost surely, 222221780 is an apocalyptic number.
22221780 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 22221780, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (35887488).
It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.
22221780 is a wasteful number, since it uses less digits than its factorization.
22221780 is an evil number, because the sum of its binary digits is even.
The square root of 22221780 is about 4713.9983029271. The cubic root of 22221780 is about 281.1423568315.
The spelling of 22221780 in words is "twenty-two million, two hundred twenty-one thousand, seven hundred eighty".