221418 has 12 divisors (see below), whose sum is σ = 479778. Its totient is φ = 73800.

The previous prime is 221413. The next prime is 221447. The reversal of 221418 is 814122.

221418 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It can be written as a sum of positive squares in only one way, i.e., 199809 + 21609 = 447^2 + 147^2 .

It is a Harshad number since it is a multiple of its sum of digits (18), and also a Moran number because the ratio is a prime number: 12301 = 221418 / (2 + 2 + 1 + 4 + 1 + 8).

It is a Curzon number.

It is a self number, because there is not a number n which added to its sum of digits gives 221418.

It is not an unprimeable number, because it can be changed into a prime (221411) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 6133 + ... + 6168.

2²²¹⁴¹⁸ is an apocalyptic number.

221418 is an abundant number, since it is smaller than the sum of its proper divisors (258360).

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

221418 is a wasteful number, since it uses less digits than its factorization.

221418 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 12309 (or 12306 counting only the distinct ones).

The product of its digits is 128, while the sum is 18.

The square root of 221418 is about 470.5507411534. The cubic root of 221418 is about 60.4975296671.

Subtracting 221418 from its reverse (814122), we obtain a cube (592704 = 84³).

The spelling of 221418 in words is "two hundred twenty-one thousand, four hundred eighteen".