81585406 has 16 divisors (see below), whose sum is σ = 140092416. Its totient is φ = 34907256.

The previous prime is 81585403. The next prime is 81585419. The reversal of 81585406 is 60458518.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81585401) 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 7 ways as a sum of consecutive naturals, for example, 4555 + ... + 13561.

It is an arithmetic number, because the mean of its divisors is an integer number (8755776).

Almost surely, 2^81585406 is an apocalyptic number.

81585406 is a deficient number, since it is larger than the sum of its proper divisors (58507010).

81585406 is a wasteful number, since it uses less digits than its factorization.

81585406 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9663.

The product of its (nonzero) digits is 38400, while the sum is 37.

The square root of 81585406 is about 9032.4640049103. The cubic root of 81585406 is about 433.7147176244.

The spelling of 81585406 in words is "eighty-one million, five hundred eighty-five thousand, four hundred six".