687917 has 2 divisors, whose sum is σ = 687918. Its totient is φ = 687916.

The previous prime is 687901. The next prime is 687923. The reversal of 687917 is 719786.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 687241 + 676 = 829^2 + 26^2 .

It is a cyclic number.

It is not a de Polignac number, because 687917 - 2⁴ = 687901 is a prime.

It is a Chen prime.

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 687917.

It is not a weakly prime, because it can be changed into another prime (687977) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 343958 + 343959.

It is an arithmetic number, because the mean of its divisors is an integer number (343959).

2⁶⁸⁷⁹¹⁷ is an apocalyptic number.

It is an amenable number.

687917 is a deficient number, since it is larger than the sum of its proper divisors (1).

687917 is an equidigital number, since it uses as much as digits as its factorization.

687917 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 21168, while the sum is 38.

The square root of 687917 is about 829.4076199312. The cubic root of 687917 is about 88.2765490827.

The spelling of 687917 in words is "six hundred eighty-seven thousand, nine hundred seventeen".