81821326344 has 64 divisors (see below), whose sum is σ = 211315875840. Its totient is φ = 26373468480.

The previous prime is 81821326339. The next prime is 81821326357. The reversal of 81821326344 is 44362312818.

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

It is a junction number, because it is equal to n+sod(n) for n = 81821326296 and 81821326305.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 930337 + ... + 1014479.

It is an arithmetic number, because the mean of its divisors is an integer number (3301810560).

Almost surely, 2^81821326344 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 81821326344, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (105657937920).

81821326344 is an abundant number, since it is smaller than the sum of its proper divisors (129494549496).

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

81821326344 is a wasteful number, since it uses less digits than its factorization.

81821326344 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 85490 (or 85486 counting only the distinct ones).

The product of its digits is 221184, while the sum is 42.

The spelling of 81821326344 in words is "eighty-one billion, eight hundred twenty-one million, three hundred twenty-six thousand, three hundred forty-four".