81865456818 has 32 divisors (see below), whose sum is σ = 168316549440. Its totient is φ = 26525620800.

The previous prime is 81865456747. The next prime is 81865456837.

81865456818 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 15 ways as a sum of consecutive naturals, for example, 57888 + ... + 408756.

It is an arithmetic number, because the mean of its divisors is an integer number (5259892170).

Almost surely, 2^81865456818 is an apocalyptic number.

81865456818 is an abundant number, since it is smaller than the sum of its proper divisors (86451092622).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

81865456818 is a wasteful number, since it uses less digits than its factorization.

81865456818 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 351962.

The product of its digits is 14745600, while the sum is 60.

The spelling of 81865456818 in words is "eighty-one billion, eight hundred sixty-five million, four hundred fifty-six thousand, eight hundred eighteen".