685511 has 2 divisors, whose sum is σ = 685512. Its totient is φ = 685510.

The previous prime is 685493. The next prime is 685513. The reversal of 685511 is 115586.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 685511 - 2¹⁴ = 669127 is a prime.

It is a super-2 number, since 2×685511² = 939850662242, which contains 22 as substring.

Together with 685513, it forms a pair of twin primes.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (685513) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 342755 + 342756.

It is an arithmetic number, because the mean of its divisors is an integer number (342756).

2⁶⁸⁵⁵¹¹ is an apocalyptic number.

685511 is a deficient number, since it is larger than the sum of its proper divisors (1).

685511 is an equidigital number, since it uses as much as digits as its factorization.

685511 is an evil number, because the sum of its binary digits is even.

The product of its digits is 1200, while the sum is 26.

The square root of 685511 is about 827.9559167009. The cubic root of 685511 is about 88.1735126817.

The spelling of 685511 in words is "six hundred eighty-five thousand, five hundred eleven".