81825856 has 56 divisors (see below), whose sum is σ = 195356480. Its totient is φ = 33219072.

The previous prime is 81825841. The next prime is 81825859. The reversal of 81825856 is 65852818.

It is a tau number, because it is divible by the number of its divisors (56).

It is not an unprimeable number, because it can be changed into a prime (81825859) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 3706 + ... + 13318.

Almost surely, 2^81825856 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 81825856, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (97678240).

81825856 is an abundant number, since it is smaller than the sum of its proper divisors (113530624).

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

81825856 is a wasteful number, since it uses less digits than its factorization.

81825856 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9651 (or 9641 counting only the distinct ones).

The product of its digits is 153600, while the sum is 43.

The square root of 81825856 is about 9045.7645337473. The cubic root of 81825856 is about 434.1403837024.

The spelling of 81825856 in words is "eighty-one million, eight hundred twenty-five thousand, eight hundred fifty-six".