81280409 has 8 divisors (see below), whose sum is σ = 95157888. Its totient is φ = 67969440.

The previous prime is 81280373. The next prime is 81280421. The reversal of 81280409 is 90408218.

It is a happy number.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a de Polignac number, because none of the positive numbers 2^k-81280409 is a prime.

It is not an unprimeable number, because it can be changed into a prime (81280709) 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, 141317 + ... + 141890.

It is an arithmetic number, because the mean of its divisors is an integer number (11894736).

Almost surely, 2^81280409 is an apocalyptic number.

It is an amenable number.

81280409 is a deficient number, since it is larger than the sum of its proper divisors (13877479).

81280409 is a wasteful number, since it uses less digits than its factorization.

81280409 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 283255.

The product of its (nonzero) digits is 4608, while the sum is 32.

The square root of 81280409 is about 9015.5648186900. The cubic root of 81280409 is about 433.1735797051.

The spelling of 81280409 in words is "eighty-one million, two hundred eighty thousand, four hundred nine".