221445220 has 24 divisors (see below), whose sum is σ = 465873408. Its totient is φ = 88418400.

The previous prime is 221445193. The next prime is 221445221. The reversal of 221445220 is 22544122.

221445220 is digitally balanced in base 3, because in such base it contains all the possibile digits an equal number of times.

It is a junction number, because it is equal to n+sod(n) for n = 221445191 and 221445200.

It is not an unprimeable number, because it can be changed into a prime (221445221) 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, 1725 + ... + 21115.

It is an arithmetic number, because the mean of its divisors is an integer number (19411392).

Almost surely, 2^221445220 is an apocalyptic number.

221445220 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

221445220 is an abundant number, since it is smaller than the sum of its proper divisors (244428188).

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

221445220 is a wasteful number, since it uses less digits than its factorization.

221445220 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 19971 (or 19969 counting only the distinct ones).

The product of its (nonzero) digits is 1280, while the sum is 22.

The square root of 221445220 is about 14881.0355822436. The cubic root of 221445220 is about 605.0000865150. Note that the first 4 decimals are identical.

Adding to 221445220 its reverse (22544122), we get a palindrome (243989342).

The spelling of 221445220 in words is "two hundred twenty-one million, four hundred forty-five thousand, two hundred twenty".