81533256 has 192 divisors, whose sum is σ = 258552000. Its totient is φ = 21288960.

The previous prime is 81533227. The next prime is 81533261. The reversal of 81533256 is 65233518.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 916060 + ... + 916148.

It is an arithmetic number, because the mean of its divisors is an integer number (1346625).

Almost surely, 2^81533256 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 81533256, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (129276000).

81533256 is an abundant number, since it is smaller than the sum of its proper divisors (177018744).

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

81533256 is a wasteful number, since it uses less digits than its factorization.

81533256 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 172 (or 161 counting only the distinct ones).

The product of its digits is 21600, while the sum is 33.

The square root of 81533256 is about 9029.5767342661. The cubic root of 81533256 is about 433.6222867000.

The spelling of 81533256 in words is "eighty-one million, five hundred thirty-three thousand, two hundred fifty-six".