831 has 4 divisors (see below), whose sum is σ = 1112. Its totient is φ = 552.

The previous prime is 829. The next prime is 839. The reversal of 831 is 138.

831 is nontrivially palindromic in base 5 and base 11.

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

It is not a de Polignac number, because 831 - 2^{1} = 829 is a prime.

It is a super-2 number, since 2×831^{2} = 1381122, which contains 22 as substring.

It is a D-number.

It is a Duffinian number.

831 is an undulating number in base 11.

831 is a lucky number.

It is a plaindrome in base 8, base 9, base 13 and base 16.

It is a nialpdrome in base 10.

It is a zygodrome in base 2.

It is a congruent number.

It is an inconsummate number, since it does not exist a number *n* which divided by its sum of digits gives 831.

It is not an unprimeable number, because it can be changed into a prime (839) 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, 136 + ... + 141.

It is an arithmetic number, because the mean of its divisors is an integer number (278).

831 is a deficient number, since it is larger than the sum of its proper divisors (281).

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

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

The sum of its prime factors is 280.

The product of its digits is 24, while the sum is 12.

The square root of 831 is about 28.8270706108. The cubic root of 831 is about 9.4015690756.

Adding to 831 its reverse (138), we get a palindrome (969).

The spelling of 831 in words is "eight hundred thirty-one", and thus it is an aban number.

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