687331 has 2 divisors, whose sum is σ = 687332. Its totient is φ = 687330.

The previous prime is 687317. The next prime is 687341. The reversal of 687331 is 133786.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 687331 - 2⁵ = 687299 is a prime.

It is a super-2 number, since 2×687331² = 944847807122, which contains 22 as substring.

687331 is a lucky number.

It is a self number, because there is not a number n which added to its sum of digits gives 687331.

It is not a weakly prime, because it can be changed into another prime (687311) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 343665 + 343666.

It is an arithmetic number, because the mean of its divisors is an integer number (343666).

2⁶⁸⁷³³¹ is an apocalyptic number.

687331 is a deficient number, since it is larger than the sum of its proper divisors (1).

687331 is an equidigital number, since it uses as much as digits as its factorization.

687331 is an evil number, because the sum of its binary digits is even.

The product of its digits is 3024, while the sum is 28.

The square root of 687331 is about 829.0542804907. The cubic root of 687331 is about 88.2514759254.

The spelling of 687331 in words is "six hundred eighty-seven thousand, three hundred thirty-one".