823 has 2 divisors, whose sum is σ = 824.
Its totient is φ = 822.
The previous prime is 821. The next prime is 827. The reversal of 823 is 328.
823 is nontrivially palindromic in base 13.
It is a weak prime.
823 is a truncatable prime.
It is a cyclic number.
It is not a de Polignac number, because 823 - 21 = 821 is a prime.
Together with 821, it forms a pair of twin primes.
823 is an undulating number in base 13.
823 is a lucky number.
It is a plaindrome in base 8, base 9, base 11, base 15 and base 16.
It is a congruent number.
It is not a weakly prime, because it can be changed into another prime (821) by changing a digit.
It is a pernicious number, because its binary representation contains a prime number (7) of ones.
It is a polite number, since it can be written as a sum of consecutive naturals, namely, 411 + 412.
It is an arithmetic number, because the mean of its divisors is an integer number (412).
2823 is an apocalyptic number.
823 is a deficient number, since it is larger than the sum of its proper divisors (1).
823 is an equidigital number, since it uses as much as digits as its factorization.
823 is an odious number, because the sum of its binary digits is odd.
The product of its digits is 48, while the sum is 13.
The square root of 823 is about 28.6879765756.
The cubic root of 823 is about 9.3713022454.
The spelling of 823 in words is "eight hundred twenty-three", and thus it is an aban number and an oban number.