221213220 has 48 divisors (see below), whose sum is σ = 620198208. Its totient is φ = 58913920.

The previous prime is 221213183. The next prime is 221213221. The reversal of 221213220 is 22312122.

It is a happy number.

221213220 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

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 221213220.

It is not an unprimeable number, because it can be changed into a prime (221213221) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 56362 + ... + 60158.

It is an arithmetic number, because the mean of its divisors is an integer number (12920796).

Almost surely, 2^221213220 is an apocalyptic number.

221213220 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

221213220 is an abundant number, since it is smaller than the sum of its proper divisors (398984988).

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

221213220 is a wasteful number, since it uses less digits than its factorization.

221213220 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4780 (or 4778 counting only the distinct ones).

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

The square root of 221213220 is about 14873.2383830825. The cubic root of 221213220 is about 604.7887339206.

Adding to 221213220 its reverse (22312122), we get a palindrome (243525342).

The spelling of 221213220 in words is "two hundred twenty-one million, two hundred thirteen thousand, two hundred twenty".