81813805158400 has 624 divisors, whose sum is σ = 243932844798720. Its totient is φ = 26626306867200.

The previous prime is 81813805158343. The next prime is 81813805158419. The reversal of 81813805158400 is 485150831818.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 1087347981 + ... + 1087423219.

Almost surely, 2^{81813805158400} is an apocalyptic number.

81813805158400 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 81813805158400, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (121966422399360).

81813805158400 is an abundant number, since it is smaller than the sum of its proper divisors (162119039640320).

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

81813805158400 is a wasteful number, since it uses less digits than its factorization.

81813805158400 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 75358 (or 75331 counting only the distinct ones).

The product of its (nonzero) digits is 1228800, while the sum is 52.

The spelling of 81813805158400 in words is "eighty-one trillion, eight hundred thirteen billion, eight hundred five million, one hundred fifty-eight thousand, four hundred".