81211211218 has 8 divisors (see below), whose sum is σ = 122020185600. Its totient is φ = 40537816020.

The previous prime is 81211211203. The next prime is 81211211219.

81211211218 is nontrivially palindromic in base 10.

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

It is not an unprimeable number, because it can be changed into a prime (81211211219) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 33893298 + ... + 33895693.

It is an arithmetic number, because the mean of its divisors is an integer number (15252523200).

Almost surely, 2^81211211218 is an apocalyptic number.

81211211218 is a deficient number, since it is larger than the sum of its proper divisors (40808974382).

81211211218 is a wasteful number, since it uses less digits than its factorization.

81211211218 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 67789592.

The product of its digits is 512, while the sum is 28.

The spelling of 81211211218 in words is "eighty-one billion, two hundred eleven million, two hundred eleven thousand, two hundred eighteen".