81080999 has 4 divisors (see below), whose sum is σ = 85348440. Its totient is φ = 76813560.

The previous prime is 81080977. The next prime is 81081001. The reversal of 81080999 is 99908018.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 81080999 - 2²⁰ = 80032423 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81080959) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2133692 + ... + 2133729.

It is an arithmetic number, because the mean of its divisors is an integer number (21337110).

Almost surely, 2^81080999 is an apocalyptic number.

81080999 is a deficient number, since it is larger than the sum of its proper divisors (4267441).

81080999 is a wasteful number, since it uses less digits than its factorization.

81080999 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4267440.

The product of its (nonzero) digits is 46656, while the sum is 44.

The square root of 81080999 is about 9004.4988200343. The cubic root of 81080999 is about 432.8190462216.

The spelling of 81080999 in words is "eighty-one million, eighty thousand, nine hundred ninety-nine".