81128459 has 4 divisors (see below), whose sum is σ = 81415416. Its totient is φ = 80841504.

The previous prime is 81128419. The next prime is 81128473. The reversal of 81128459 is 95482118.

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

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-81128459 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (81128419) 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, 143054 + ... + 143619.

It is an arithmetic number, because the mean of its divisors is an integer number (20353854).

Almost surely, 2^81128459 is an apocalyptic number.

81128459 is a deficient number, since it is larger than the sum of its proper divisors (286957).

81128459 is a wasteful number, since it uses less digits than its factorization.

81128459 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 286956.

The product of its digits is 23040, while the sum is 38.

The square root of 81128459 is about 9007.1337838405. The cubic root of 81128459 is about 432.9034786022.

The spelling of 81128459 in words is "eighty-one million, one hundred twenty-eight thousand, four hundred fifty-nine".