81818218 has 8 divisors (see below), whose sum is σ = 129186720. Its totient is φ = 38755980.

The previous prime is 81818197. The next prime is 81818227. The reversal of 81818218 is 81281818.

It is a happy number.

It is a sphenic number, since it is the product of 3 distinct primes.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1076518 + ... + 1076593.

It is an arithmetic number, because the mean of its divisors is an integer number (16148340).

Almost surely, 2^81818218 is an apocalyptic number.

81818218 is a deficient number, since it is larger than the sum of its proper divisors (47368502).

81818218 is a wasteful number, since it uses less digits than its factorization.

81818218 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2153132.

The product of its digits is 8192, while the sum is 37.

The square root of 81818218 is about 9045.3423373579. The cubic root of 81818218 is about 434.1268750651.

The spelling of 81818218 in words is "eighty-one million, eight hundred eighteen thousand, two hundred eighteen".