81506466 has 64 divisors (see below), whose sum is σ = 201916800. Its totient is φ = 24219648.

The previous prime is 81506377. The next prime is 81506473. The reversal of 81506466 is 66460518.

81506466 is a `hidden beast` number, since 8 + 1 + 5 + 0 + 646 + 6 = 666.

It is a self number, because there is not a number n which added to its sum of digits gives 81506466.

It is a congruent number.

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 31 ways as a sum of consecutive naturals, for example, 15106 + ... + 19778.

It is an arithmetic number, because the mean of its divisors is an integer number (3154950).

Almost surely, 2^81506466 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 81506466, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (100958400).

81506466 is an abundant number, since it is smaller than the sum of its proper divisors (120410334).

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

81506466 is a wasteful number, since it uses less digits than its factorization.

81506466 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4720 (or 4714 counting only the distinct ones).

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

The square root of 81506466 is about 9028.0931541494. The cubic root of 81506466 is about 433.5747886434.

The spelling of 81506466 in words is "eighty-one million, five hundred six thousand, four hundred sixty-six".