81291834400 has 144 divisors (see below), whose sum is σ = 238741594560. Its totient is φ = 26404531200.

The previous prime is 81291834397. The next prime is 81291834401. The reversal of 81291834400 is 443819218.

It is a Harshad number since it is a multiple of its sum of digits (40).

It is not an unprimeable number, because it can be changed into a prime (81291834401) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 275611 + ... + 488410.

It is an arithmetic number, because the mean of its divisors is an integer number (1657927740).

Almost surely, 2^81291834400 is an apocalyptic number.

81291834400 is a gapful number since it is divisible by the number (80) formed by its first and last digit.

It is an amenable number.

81291834400 is an abundant number, since it is smaller than the sum of its proper divisors (157449760160).

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

81291834400 is a wasteful number, since it uses less digits than its factorization.

81291834400 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 764067 (or 764054 counting only the distinct ones).

The product of its (nonzero) digits is 55296, while the sum is 40.

The spelling of 81291834400 in words is "eighty-one billion, two hundred ninety-one million, eight hundred thirty-four thousand, four hundred".