819281 has 4 divisors (see below), whose sum is σ = 867492. Its totient is φ = 771072.

The previous prime is 819271. The next prime is 819289. The reversal of 819281 is 182918.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 182918 = 2 ⋅91459.

It can be written as a sum of positive squares in 2 ways, for example, as 625681 + 193600 = 791^2 + 440^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-819281 is a prime.

It is a super-2 number, since 2×819281² = 1342442713922, which contains 22 as substring.

It is a Duffinian number.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (819289) 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, 24080 + ... + 24113.

It is an arithmetic number, because the mean of its divisors is an integer number (216873).

2⁸¹⁹²⁸¹ is an apocalyptic number.

It is an amenable number.

819281 is a deficient number, since it is larger than the sum of its proper divisors (48211).

819281 is a wasteful number, since it uses less digits than its factorization.

819281 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 48210.

The product of its digits is 1152, while the sum is 29.

The square root of 819281 is about 905.1414254137. The cubic root of 819281 is about 93.5716514461.

The spelling of 819281 in words is "eight hundred nineteen thousand, two hundred eighty-one".