81825842240 has 28 divisors (see below), whose sum is σ = 194847787596. Its totient is φ = 32730336768.

The previous prime is 81825842237. The next prime is 81825842251. The reversal of 81825842240 is 4224852818.

It is a happy number.

It can be written as a sum of positive squares in 2 ways, for example, as 29881962496 + 51943879744 = 172864^2 + 227912^2 .

It is a junction number, because it is equal to n+sod(n) for n = 81825842191 and 81825842200.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 127852559 + ... + 127853198.

It is an arithmetic number, because the mean of its divisors is an integer number (6958849557).

Almost surely, 2^81825842240 is an apocalyptic number.

81825842240 is a gapful number since it is divisible by the number (80) formed by its first and last digit.

It is an amenable number.

81825842240 is an abundant number, since it is smaller than the sum of its proper divisors (113021945356).

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

81825842240 is a wasteful number, since it uses less digits than its factorization.

81825842240 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 255705774 (or 255705764 counting only the distinct ones).

The product of its (nonzero) digits is 327680, while the sum is 44.

The spelling of 81825842240 in words is "eighty-one billion, eight hundred twenty-five million, eight hundred forty-two thousand, two hundred forty".