687823 has 2 divisors, whose sum is σ = 687824. Its totient is φ = 687822.

The previous prime is 687809. The next prime is 687829. The reversal of 687823 is 328786.

It is a happy number.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 687823 - 2⁹ = 687311 is a prime.

It is an Ulam number.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (687829) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 343911 + 343912.

It is an arithmetic number, because the mean of its divisors is an integer number (343912).

2⁶⁸⁷⁸²³ is an apocalyptic number.

687823 is a deficient number, since it is larger than the sum of its proper divisors (1).

687823 is an equidigital number, since it uses as much as digits as its factorization.

687823 is an evil number, because the sum of its binary digits is even.

The product of its digits is 16128, while the sum is 34.

The square root of 687823 is about 829.3509510455. The cubic root of 687823 is about 88.2725280678.

The spelling of 687823 in words is "six hundred eighty-seven thousand, eight hundred twenty-three".