81812584 has 32 divisors (see below), whose sum is σ = 175996800. Its totient is φ = 34925760.

The previous prime is 81812581. The next prime is 81812603. The reversal of 81812584 is 48521818.

It is a happy number.

It is not an unprimeable number, because it can be changed into a prime (81812581) by changing a digit.

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 7 ways as a sum of consecutive naturals, for example, 12349 + ... + 17779.

It is an arithmetic number, because the mean of its divisors is an integer number (5499900).

Almost surely, 2^81812584 is an apocalyptic number.

It is an amenable number.

81812584 is an abundant number, since it is smaller than the sum of its proper divisors (94184216).

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

81812584 is a wasteful number, since it uses less digits than its factorization.

81812584 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5713 (or 5709 counting only the distinct ones).

The product of its digits is 20480, while the sum is 37.

The square root of 81812584 is about 9045.0309009975. The cubic root of 81812584 is about 434.1169101819.

The spelling of 81812584 in words is "eighty-one million, eight hundred twelve thousand, five hundred eighty-four".