81347843512320 has 2304 divisors, whose sum is σ = 343664919037440. Its totient is φ = 16231012761600.

The previous prime is 81347843512303. The next prime is 81347843512391. The reversal of 81347843512320 is 2321534874318.

It is a super-2 number, since 2×81347843512320² (a number of 29 digits) contains 22 as substring.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 191 ways as a sum of consecutive naturals, for example, 43431842904 + ... + 43431844776.

It is an arithmetic number, because the mean of its divisors is an integer number (149160121110).

Almost surely, 2^{81347843512320} is an apocalyptic number.

81347843512320 is a gapful number since it is divisible by the number (80) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 81347843512320, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (171832459518720).

81347843512320 is an abundant number, since it is smaller than the sum of its proper divisors (262317075525120).

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

81347843512320 is a wasteful number, since it uses less digits than its factorization.

81347843512320 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2032 (or 2005 counting only the distinct ones).

The product of its (nonzero) digits is 3870720, while the sum is 51.

The spelling of 81347843512320 in words is "eighty-one trillion, three hundred forty-seven billion, eight hundred forty-three million, five hundred twelve thousand, three hundred twenty".