81814343872 has 56 divisors (see below), whose sum is σ = 165391165280. Its totient is φ = 40144066560.

The previous prime is 81814343869. The next prime is 81814343879. The reversal of 81814343872 is 27834341818.

It is an alternating number because its digits alternate between even and odd.

It is not an unprimeable number, because it can be changed into a prime (81814343879) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1689988 + ... + 1737724.

Almost surely, 2^81814343872 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 81814343872, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (82695582640).

81814343872 is an abundant number, since it is smaller than the sum of its proper divisors (83576821408).

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

81814343872 is a wasteful number, since it uses less digits than its factorization.

81814343872 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 48249 (or 48239 counting only the distinct ones).

The product of its digits is 1032192, while the sum is 49.

The spelling of 81814343872 in words is "eighty-one billion, eight hundred fourteen million, three hundred forty-three thousand, eight hundred seventy-two".