840823 has 2 divisors, whose sum is σ = 840824. Its totient is φ = 840822.

The previous prime is 840821. The next prime is 840839. The reversal of 840823 is 328048.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 840823 - 2¹ = 840821 is a prime.

Together with 840821, it forms a pair of twin primes.

840823 is a lucky number.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (840821) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 420411 + 420412.

It is an arithmetic number, because the mean of its divisors is an integer number (420412).

2⁸⁴⁰⁸²³ is an apocalyptic number.

840823 is a deficient number, since it is larger than the sum of its proper divisors (1).

840823 is an equidigital number, since it uses as much as digits as its factorization.

840823 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 1536, while the sum is 25.

The square root of 840823 is about 916.9640123800. The cubic root of 840823 is about 94.3846843270.

The spelling of 840823 in words is "eight hundred forty thousand, eight hundred twenty-three".