7218229 has 4 divisors (see below), whose sum is σ = 7354476. Its totient is φ = 7081984.

The previous prime is 7218227. The next prime is 7218247. The reversal of 7218229 is 9228127.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 9228127 = 17 ⋅542831.

It can be written as a sum of positive squares in 2 ways, for example, as 2387025 + 4831204 = 1545^2 + 2198^2 .

It is a cyclic number.

It is not a de Polignac number, because 7218229 - 2¹ = 7218227 is a prime.

It is a Smith number, since the sum of its digits (31) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a Duffinian number.

7218229 is a lucky number.

It is a self number, because there is not a number n which added to its sum of digits gives 7218229.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (7218221) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 68044 + ... + 68149.

It is an arithmetic number, because the mean of its divisors is an integer number (1838619).

Almost surely, 2^7218229 is an apocalyptic number.

It is an amenable number.

7218229 is a deficient number, since it is larger than the sum of its proper divisors (136247).

7218229 is a wasteful number, since it uses less digits than its factorization.

7218229 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 136246.

The product of its digits is 4032, while the sum is 31.

The square root of 7218229 is about 2686.6761993214. The cubic root of 7218229 is about 193.2607016773.

It can be divided in two parts, 7218 and 229, that added together give a palindrome (7447).

The spelling of 7218229 in words is "seven million, two hundred eighteen thousand, two hundred twenty-nine".