81725856 has 96 divisors (see below), whose sum is σ = 223534080. Its totient is φ = 26125056.

The previous prime is 81725849. The next prime is 81725869. The reversal of 81725856 is 65852718.

It is a tau number, because it is divible by the number of its divisors (96).

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 266055 + ... + 266361.

It is an arithmetic number, because the mean of its divisors is an integer number (2328480).

Almost surely, 2^81725856 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 81725856, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (111767040).

81725856 is an abundant number, since it is smaller than the sum of its proper divisors (141808224).

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

81725856 is a wasteful number, since it uses less digits than its factorization.

81725856 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 426 (or 418 counting only the distinct ones).

The product of its digits is 134400, while the sum is 42.

The square root of 81725856 is about 9040.2353951653. The cubic root of 81725856 is about 433.9634561881.

It can be divided in two parts, 8172 and 5856, that added together give a triangular number (14028 = T₁₆₇).

The spelling of 81725856 in words is "eighty-one million, seven hundred twenty-five thousand, eight hundred fifty-six".