81815823360 has 352 divisors, whose sum is σ = 291832110720. Its totient is φ = 21737078784.

The previous prime is 81815823359. The next prime is 81815823377. The reversal of 81815823360 is 6332851818.

81815823360 is a `hidden beast` number, since 8 + 1 + 8 + 1 + 582 + 3 + 3 + 60 = 666.

It is a Harshad number since it is a multiple of its sum of digits (45).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 43821147 + ... + 43823013.

Almost surely, 2^81815823360 is an apocalyptic number.

81815823360 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 81815823360, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (145916055360).

81815823360 is an abundant number, since it is smaller than the sum of its proper divisors (210016287360).

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

81815823360 is a wasteful number, since it uses less digits than its factorization.

81815823360 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2218 (or 2194 counting only the distinct ones).

The product of its (nonzero) digits is 276480, while the sum is 45.

The spelling of 81815823360 in words is "eighty-one billion, eight hundred fifteen million, eight hundred twenty-three thousand, three hundred sixty".