81345178800 has 480 divisors, whose sum is σ = 305902444800. Its totient is φ = 20473896960.

The previous prime is 81345178799. The next prime is 81345178867. The reversal of 81345178800 is 887154318.

It is a happy number.

It is a super-2 number, since 2×81345178800² (a number of 23 digits) contains 22 as substring.

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

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 95 ways as a sum of consecutive naturals, for example, 72435039 + ... + 72436161.

It is an arithmetic number, because the mean of its divisors is an integer number (637296760).

Almost surely, 2^81345178800 is an apocalyptic number.

81345178800 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 81345178800, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (152951222400).

81345178800 is an abundant number, since it is smaller than the sum of its proper divisors (224557266000).

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

81345178800 is a wasteful number, since it uses less digits than its factorization.

81345178800 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1522 (or 1505 counting only the distinct ones).

The product of its (nonzero) digits is 215040, while the sum is 45.

The spelling of 81345178800 in words is "eighty-one billion, three hundred forty-five million, one hundred seventy-eight thousand, eight hundred".