687309 has 16 divisors (see below), whose sum is σ = 1093632. Its totient is φ = 375408.

The previous prime is 687307. The next prime is 687311. The reversal of 687309 is 903786.

It is a happy number.

It is an interprime number because it is at equal distance from previous prime (687307) and next prime (687311).

It is not a de Polignac number, because 687309 - 2¹ = 687307 is a prime.

It is a super-2 number, since 2×687309² = 944787322962, which contains 22 as substring.

It is a Curzon number.

It is a self number, because there is not a number n which added to its sum of digits gives 687309.

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 687309.

It is not an unprimeable number, because it can be changed into a prime (687307) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 229 + ... + 1194.

It is an arithmetic number, because the mean of its divisors is an integer number (68352).

2⁶⁸⁷³⁰⁹ is an apocalyptic number.

687309 is a gapful number since it is divisible by the number (69) formed by its first and last digit.

It is an amenable number.

687309 is a deficient number, since it is larger than the sum of its proper divisors (406323).

687309 is a wasteful number, since it uses less digits than its factorization.

687309 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1456.

The product of its (nonzero) digits is 9072, while the sum is 33.

The square root of 687309 is about 829.0410122545. The cubic root of 687309 is about 88.2505343348.

The spelling of 687309 in words is "six hundred eighty-seven thousand, three hundred nine".