81080809 has 16 divisors (see below), whose sum is σ = 87552000. Its totient is φ = 74854800.

The previous prime is 81080807. The next prime is 81080851. The reversal of 81080809 is 90808018.

It is a cyclic number.

It is not a de Polignac number, because 81080809 - 2¹ = 81080807 is a prime.

It is not an unprimeable number, because it can be changed into a prime (81080807) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 169032 + ... + 169510.

It is an arithmetic number, because the mean of its divisors is an integer number (5472000).

Almost surely, 2^81080809 is an apocalyptic number.

It is an amenable number.

81080809 is a deficient number, since it is larger than the sum of its proper divisors (6471191).

81080809 is a wasteful number, since it uses less digits than its factorization.

81080809 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 708.

The product of its (nonzero) digits is 4608, while the sum is 34.

The square root of 81080809 is about 9004.4882697464. The cubic root of 81080809 is about 432.8187081412.

The spelling of 81080809 in words is "eighty-one million, eighty thousand, eight hundred nine".