81218211281218 has 32 divisors (see below), whose sum is σ = 133042930935552. Its totient is φ = 36878388316800.

The previous prime is 81218211281167. The next prime is 81218211281231.

81218211281218 is nontrivially palindromic in base 10.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 79051248 + ... + 80072068.

It is an arithmetic number, because the mean of its divisors is an integer number (4157591591736).

Almost surely, 2^{81218211281218} is an apocalyptic number.

81218211281218 is a deficient number, since it is larger than the sum of its proper divisors (51824719654334).

81218211281218 is a wasteful number, since it uses less digits than its factorization.

81218211281218 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1024650.

The product of its digits is 65536, while the sum is 46.

The spelling of 81218211281218 in words is "eighty-one trillion, two hundred eighteen billion, two hundred eleven million, two hundred eighty-one thousand, two hundred eighteen".