81213431218 has 8 divisors (see below), whose sum is σ = 122269668480. Its totient is φ = 40456875060.

The previous prime is 81213431209. The next prime is 81213431239.

81213431218 is nontrivially palindromic in base 10.

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

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 74919598 + ... + 74920681.

It is an arithmetic number, because the mean of its divisors is an integer number (15283708560).

Almost surely, 2^81213431218 is an apocalyptic number.

81213431218 is a deficient number, since it is larger than the sum of its proper divisors (41056237262).

81213431218 is a wasteful number, since it uses less digits than its factorization.

81213431218 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 149840552.

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

The spelling of 81213431218 in words is "eighty-one billion, two hundred thirteen million, four hundred thirty-one thousand, two hundred eighteen".