221123220 has 24 divisors (see below), whose sum is σ = 619145184. Its totient is φ = 58966176.

The previous prime is 221123213. The next prime is 221123251. The reversal of 221123220 is 22321122.

It is a happy number.

It is a Harshad number since it is a multiple of its sum of digits (15).

It is a self number, because there is not a number n which added to its sum of digits gives 221123220.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1842634 + ... + 1842753.

It is an arithmetic number, because the mean of its divisors is an integer number (25797716).

Almost surely, 2^221123220 is an apocalyptic number.

221123220 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

221123220 is an abundant number, since it is smaller than the sum of its proper divisors (398021964).

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

221123220 is a wasteful number, since it uses less digits than its factorization.

221123220 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3685399 (or 3685397 counting only the distinct ones).

The product of its (nonzero) digits is 96, while the sum is 15.

The square root of 221123220 is about 14870.2125068877. The cubic root of 221123220 is about 604.7067039084.

Adding to 221123220 its reverse (22321122), we get a palindrome (243444342).

The spelling of 221123220 in words is "two hundred twenty-one million, one hundred twenty-three thousand, two hundred twenty".