81418773312 has 84 divisors (see below), whose sum is σ = 233563826496. Its totient is φ = 27117308160.

The previous prime is 81418773301. The next prime is 81418773367. The reversal of 81418773312 is 21337781418.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 651643 + ... + 766469.

It is an arithmetic number, because the mean of its divisors is an integer number (2780521744).

Almost surely, 2^81418773312 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 81418773312, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (116781913248).

81418773312 is an abundant number, since it is smaller than the sum of its proper divisors (152145053184).

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

81418773312 is a wasteful number, since it uses less digits than its factorization.

81418773312 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 116076 (or 116063 counting only the distinct ones).

The product of its digits is 225792, while the sum is 45.

The spelling of 81418773312 in words is "eighty-one billion, four hundred eighteen million, seven hundred seventy-three thousand, three hundred twelve".