812081571840 has 1728 divisors, whose sum is σ = 3715111370880. Its totient is φ = 159358648320.

The previous prime is 812081571797. The next prime is 812081571841. The reversal of 812081571840 is 48175180218.

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

It is not an unprimeable number, because it can be changed into a prime (812081571841) by changing a digit.

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 143 ways as a sum of consecutive naturals, for example, 2561771362 + ... + 2561771678.

It is an arithmetic number, because the mean of its divisors is an integer number (2149948710).

Almost surely, 2^812081571840 is an apocalyptic number.

812081571840 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 812081571840, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1857555685440).

812081571840 is an abundant number, since it is smaller than the sum of its proper divisors (2903029799040).

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

812081571840 is a wasteful number, since it uses less digits than its factorization.

812081571840 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 406 (or 364 counting only the distinct ones).

The product of its (nonzero) digits is 143360, while the sum is 45.

The spelling of 812081571840 in words is "eight hundred twelve billion, eighty-one million, five hundred seventy-one thousand, eight hundred forty".