221738220 has 144 divisors (see below), whose sum is σ = 747950112. Its totient is φ = 52715520.

The previous prime is 221738207. The next prime is 221738261. The reversal of 221738220 is 22837122.

It is a happy number.

It is a hoax number, since the sum of its digits (27) coincides with the sum of the digits of its distinct prime factors.

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 47 ways as a sum of consecutive naturals, for example, 103884 + ... + 105996.

It is an arithmetic number, because the mean of its divisors is an integer number (5194098).

Almost surely, 2^221738220 is an apocalyptic number.

221738220 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 221738220, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (373975056).

221738220 is an abundant number, since it is smaller than the sum of its proper divisors (526211892).

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

221738220 is a wasteful number, since it uses less digits than its factorization.

221738220 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2192 (or 2187 counting only the distinct ones).

The product of its (nonzero) digits is 2688, while the sum is 27.

The square root of 221738220 is about 14890.8770728927. The cubic root of 221738220 is about 605.2667994315.

The spelling of 221738220 in words is "two hundred twenty-one million, seven hundred thirty-eight thousand, two hundred twenty".