81222218 has 24 divisors (see below), whose sum is σ = 153050016. Its totient is φ = 31644360.

The previous prime is 81222203. The next prime is 81222221.

81222218 is nontrivially palindromic in base 10.

It is a Curzon number.

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 22280 + ... + 25667.

It is an arithmetic number, because the mean of its divisors is an integer number (6377084).

Almost surely, 2^81222218 is an apocalyptic number.

81222218 is a deficient number, since it is larger than the sum of its proper divisors (71827798).

81222218 is a wasteful number, since it uses less digits than its factorization.

81222218 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 47978 (or 47967 counting only the distinct ones).

The product of its digits is 1024, while the sum is 26.

The square root of 81222218 is about 9012.3369888171. The cubic root of 81222218 is about 433.0701811867.

The spelling of 81222218 in words is "eighty-one million, two hundred twenty-two thousand, two hundred eighteen".