81337011840 has 1280 divisors, whose sum is σ = 358293196800. Its totient is φ = 17169408000.

The previous prime is 81337011827. The next prime is 81337011851. The reversal of 81337011840 is 4811073318.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a junction number, because it is equal to n+sod(n) for n = 81337011795 and 81337011804.

It is an unprimeable number.

It is a polite number, since it can be written in 159 ways as a sum of consecutive naturals, for example, 324051715 + ... + 324051965.

It is an arithmetic number, because the mean of its divisors is an integer number (279916560).

Almost surely, 2^81337011840 is an apocalyptic number.

81337011840 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 81337011840, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (179146598400).

81337011840 is an abundant number, since it is smaller than the sum of its proper divisors (276956184960).

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

81337011840 is a wasteful number, since it uses less digits than its factorization.

81337011840 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 355 (or 334 counting only the distinct ones).

The product of its (nonzero) digits is 16128, while the sum is 36.

The spelling of 81337011840 in words is "eighty-one billion, three hundred thirty-seven million, eleven thousand, eight hundred forty".