81233218 has 16 divisors (see below), whose sum is σ = 136170720. Its totient is φ = 36023200.

The previous prime is 81233209. The next prime is 81233219.

81233218 is nontrivially palindromic in base 10.

It is not an unprimeable number, because it can be changed into a prime (81233219) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 44128 + ... + 45931.

It is an arithmetic number, because the mean of its divisors is an integer number (8510670).

Almost surely, 2^81233218 is an apocalyptic number.

81233218 is a deficient number, since it is larger than the sum of its proper divisors (54937502).

81233218 is a wasteful number, since it uses less digits than its factorization.

81233218 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 90113.

The product of its digits is 2304, while the sum is 28.

The square root of 81233218 is about 9012.9472427170. The cubic root of 81233218 is about 433.0897306691.

The spelling of 81233218 in words is "eighty-one million, two hundred thirty-three thousand, two hundred eighteen".