221612220 has 48 divisors (see below), whose sum is σ = 689461920. Its totient is φ = 59096448.

The previous prime is 221612189. The next prime is 221612227. The reversal of 221612220 is 22216122.

221612220 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a super-2 number, since 2×221612220² = 98223952106656800, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (18).

It is a junction number, because it is equal to n+sod(n) for n = 221612193 and 221612202.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (221612227) 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, 204657 + ... + 205736.

It is an arithmetic number, because the mean of its divisors is an integer number (14363790).

Almost surely, 2^221612220 is an apocalyptic number.

221612220 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

221612220 is an abundant number, since it is smaller than the sum of its proper divisors (467849700).

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

221612220 is a wasteful number, since it uses less digits than its factorization.

221612220 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 410411 (or 410403 counting only the distinct ones).

The product of its (nonzero) digits is 192, while the sum is 18.

The square root of 221612220 is about 14886.6456933723. The cubic root of 221612220 is about 605.1521325861.

Adding to 221612220 its reverse (22216122), we get a palindrome (243828342).

The spelling of 221612220 in words is "two hundred twenty-one million, six hundred twelve thousand, two hundred twenty".