72218 has 4 divisors (see below), whose sum is σ = 108330. Its totient is φ = 36108.

The previous prime is 72211. The next prime is 72221. The reversal of 72218 is 81227.

72218 = 72² + 73² + ... + 83².

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 81227 = 43 ⋅1889.

It can be written as a sum of positive squares in only one way, i.e., 37249 + 34969 = 193^2 + 187^2 .

It is a self number, because there is not a number n which added to its sum of digits gives 72218.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 72218.

It is not an unprimeable number, because it can be changed into a prime (72211) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 18053 + ... + 18056.

2⁷²²¹⁸ is an apocalyptic number.

72218 is a deficient number, since it is larger than the sum of its proper divisors (36112).

72218 is a wasteful number, since it uses less digits than its factorization.

72218 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 36111.

The product of its digits is 224, while the sum is 20.

The square root of 72218 is about 268.7340692953. The cubic root of 72218 is about 41.6436210337.

Subtracting 72218 from its reverse (81227), we obtain a palindrome (9009).

It can be divided in two parts, 722 and 18, that multiplied together give a square (12996 = 114²).

The spelling of 72218 in words is "seventy-two thousand, two hundred eighteen".