81273943296 has 864 divisors, whose sum is σ = 306236985600. Its totient is φ = 21361729536.

The previous prime is 81273943277. The next prime is 81273943313. The reversal of 81273943296 is 69234937218.

81273943296 is a `hidden beast` number, since 81 + 273 + 9 + 4 + 3 + 296 = 666.

It is a tau number, because it is divible by the number of its divisors (864).

It is a Harshad number since it is a multiple of its sum of digits (54).

It is a nude number because it is divisible by every one of its digits.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 95 ways as a sum of consecutive naturals, for example, 277385326 + ... + 277385618.

Almost surely, 2^81273943296 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 81273943296, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (153118492800).

81273943296 is an abundant number, since it is smaller than the sum of its proper divisors (224963042304).

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

81273943296 is an equidigital number, since it uses as much as digits as its factorization.

81273943296 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 358 (or 318 counting only the distinct ones).

The product of its digits is 3919104, while the sum is 54.

The spelling of 81273943296 in words is "eighty-one billion, two hundred seventy-three million, nine hundred forty-three thousand, two hundred ninety-six".