81579578 has 16 divisors (see below), whose sum is σ = 129030720. Its totient is φ = 38576736.

The previous prime is 81579571. The next prime is 81579599. The reversal of 81579578 is 87597518.

It is not an unprimeable number, because it can be changed into a prime (81579571) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 26150 + ... + 29102.

It is an arithmetic number, because the mean of its divisors is an integer number (8064420).

Almost surely, 2^81579578 is an apocalyptic number.

81579578 is a deficient number, since it is larger than the sum of its proper divisors (47451142).

81579578 is a wasteful number, since it uses less digits than its factorization.

81579578 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3701.

The product of its digits is 705600, while the sum is 50.

The square root of 81579578 is about 9032.1413850759. The cubic root of 81579578 is about 433.7043900030.

The spelling of 81579578 in words is "eighty-one million, five hundred seventy-nine thousand, five hundred seventy-eight".