5×81

5×81 is the product of the integers 5 and 81. In base-10 arithmetic, the result is 405. The expression combines a small multiplier with a relatively large factor that itself is a power of 3 (81 = 3^4, and also 9^2).

From a factorization perspective, 5×81 can be written as 5 × 3^4, giving the prime factorization 3^4 × 5. This shows that the number is composed entirely of the primes 3 and 5, with 3 raised to the fourth power and a single factor of 5.

In decimal form, the value remains 405. Representations in other bases are: binary 110010101, octal 625, and hexadecimal 0x195. These alternate bases reflect the same quantity using different numeral systems.

Divisors of 405 follow from its prime factorization 3^4 × 5. The positive divisors are 3^a × 5^b for a = 0,1,2,3,4 and b = 0,1, yielding the set {1, 3, 9, 27, 81, 5, 15, 45, 135, 405}. Consequently, 405 has 10 divisors in total.

Contextually, 81 is a perfect power (a square and a power of 3), so multiplying by 5 offers a straightforward example of scaling a power by an integer. The number 405 appears in various mathematical contexts as a simple composite with a clear prime structure and multiple factorization forms.