81256266 has 96 divisors (see below), whose sum is σ = 219098880. Its totient is φ = 21192192.

The previous prime is 81256249. The next prime is 81256267. The reversal of 81256266 is 66265218.

81256266 is a `hidden beast` number, since 8 + 1 + 25 + 626 + 6 = 666.

It is a Curzon number.

It is a self number, because there is not a number n which added to its sum of digits gives 81256266.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81256267) 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 47 ways as a sum of consecutive naturals, for example, 184875 + ... + 185313.

It is an arithmetic number, because the mean of its divisors is an integer number (2282280).

Almost surely, 2^81256266 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 81256266, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (109549440).

81256266 is an abundant number, since it is smaller than the sum of its proper divisors (137842614).

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

81256266 is a wasteful number, since it uses less digits than its factorization.

81256266 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 580 (or 577 counting only the distinct ones).

The product of its digits is 34560, while the sum is 36.

The square root of 81256266 is about 9014.2257571019. The cubic root of 81256266 is about 433.1306864442.

The spelling of 81256266 in words is "eighty-one million, two hundred fifty-six thousand, two hundred sixty-six".