221806220 has 24 divisors (see below), whose sum is σ = 466527600. Its totient is φ = 88582592.

The previous prime is 221806141. The next prime is 221806229. The reversal of 221806220 is 22608122.

221806220 is digitally balanced in base 3, because in such base it contains all the possibile digits an equal number of times.

It is not an unprimeable number, because it can be changed into a prime (221806229) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 4766 + ... + 21594.

It is an arithmetic number, because the mean of its divisors is an integer number (19438650).

Almost surely, 2^221806220 is an apocalyptic number.

221806220 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

221806220 is an abundant number, since it is smaller than the sum of its proper divisors (244721380).

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

221806220 is a wasteful number, since it uses less digits than its factorization.

221806220 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 17497 (or 17495 counting only the distinct ones).

The product of its (nonzero) digits is 768, while the sum is 23.

The square root of 221806220 is about 14893.1601750602. The cubic root of 221806220 is about 605.3286650792.

The spelling of 221806220 in words is "two hundred twenty-one million, eight hundred six thousand, two hundred twenty".