81266218 has 16 divisors (see below), whose sum is σ = 133140384. Its totient is φ = 36894960.

The previous prime is 81266203. The next prime is 81266219.

81266218 is nontrivially palindromic in base 10.

It is not an unprimeable number, because it can be changed into a prime (81266219) 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, 22921 + ... + 26227.

It is an arithmetic number, because the mean of its divisors is an integer number (8321274).

Almost surely, 2^81266218 is an apocalyptic number.

81266218 is a deficient number, since it is larger than the sum of its proper divisors (51874166).

81266218 is a wasteful number, since it uses less digits than its factorization.

81266218 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4437.

The product of its digits is 9216, while the sum is 34.

The square root of 81266218 is about 9014.7777565506. Note that the first 4 decimals coincide. The cubic root of 81266218 is about 433.1483685293.

The spelling of 81266218 in words is "eighty-one million, two hundred sixty-six thousand, two hundred eighteen".