685987 has 2 divisors, whose sum is σ = 685988. Its totient is φ = 685986.

The previous prime is 685973. The next prime is 685991. The reversal of 685987 is 789586.

It is a happy number.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 685987 - 2⁷ = 685859 is a prime.

It is not a weakly prime, because it can be changed into another prime (685907) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 342993 + 342994.

It is an arithmetic number, because the mean of its divisors is an integer number (342994).

2⁶⁸⁵⁹⁸⁷ is an apocalyptic number.

685987 is a deficient number, since it is larger than the sum of its proper divisors (1).

685987 is an equidigital number, since it uses as much as digits as its factorization.

685987 is an evil number, because the sum of its binary digits is even.

The product of its digits is 120960, while the sum is 43.

The square root of 685987 is about 828.2433217358. The cubic root of 685987 is about 88.1939163812.

The spelling of 685987 in words is "six hundred eighty-five thousand, nine hundred eighty-seven".