221840220 has 48 divisors (see below), whose sum is σ = 709890048. Its totient is φ = 50706240.

The previous prime is 221840209. The next prime is 221840231. The reversal of 221840220 is 22048122.

It is a happy number.

It is an interprime number because it is at equal distance from previous prime (221840209) and next prime (221840231).

It is a Harshad number since it is a multiple of its sum of digits (21).

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 263676 + ... + 264515.

It is an arithmetic number, because the mean of its divisors is an integer number (14789376).

Almost surely, 2^221840220 is an apocalyptic number.

221840220 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

221840220 is an abundant number, since it is smaller than the sum of its proper divisors (488049828).

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

221840220 is a wasteful number, since it uses less digits than its factorization.

221840220 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 528210 (or 528208 counting only the distinct ones).

The product of its (nonzero) digits is 512, while the sum is 21.

The square root of 221840220 is about 14894.3015949053. The cubic root of 221840220 is about 605.3595931615.

Adding to 221840220 its reverse (22048122), we get a palindrome (243888342).

The spelling of 221840220 in words is "two hundred twenty-one million, eight hundred forty thousand, two hundred twenty".