81406584 has 48 divisors (see below), whose sum is σ = 251974320. Its totient is φ = 23258880.

The previous prime is 81406553. The next prime is 81406603. The reversal of 81406584 is 48560418.

It is a Harshad number since it is a multiple of its sum of digits (36).

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 11 ways as a sum of consecutive naturals, for example, 80257 + ... + 81264.

It is an arithmetic number, because the mean of its divisors is an integer number (5249465).

Almost surely, 2^81406584 is an apocalyptic number.

81406584 is a gapful number since it is divisible by the number (84) formed by its first and last digit.

It is an amenable number.

81406584 is an abundant number, since it is smaller than the sum of its proper divisors (170567736).

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

81406584 is a wasteful number, since it uses less digits than its factorization.

81406584 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 161540 (or 161533 counting only the distinct ones).

The product of its (nonzero) digits is 30720, while the sum is 36.

The square root of 81406584 is about 9022.5597254881. The cubic root of 81406584 is about 433.3976083488.

The spelling of 81406584 in words is "eighty-one million, four hundred six thousand, five hundred eighty-four".