685801 has 4 divisors (see below), whose sum is σ = 687492. Its totient is φ = 684112.

The previous prime is 685793. The next prime is 685819. The reversal of 685801 is 108586.

It is a happy number.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 108586 = 2 ⋅54293.

It can be written as a sum of positive squares in 2 ways, for example, as 331776 + 354025 = 576^2 + 595^2 .

It is a cyclic number.

It is not a de Polignac number, because 685801 - 2³ = 685793 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 685801.

It is not an unprimeable number, because it can be changed into a prime (685001) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 171 + ... + 1183.

It is an arithmetic number, because the mean of its divisors is an integer number (171873).

2⁶⁸⁵⁸⁰¹ is an apocalyptic number.

It is an amenable number.

685801 is a deficient number, since it is larger than the sum of its proper divisors (1691).

685801 is a wasteful number, since it uses less digits than its factorization.

685801 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1690.

The product of its (nonzero) digits is 1920, while the sum is 28.

The square root of 685801 is about 828.1310282799. The cubic root of 685801 is about 88.1859446308.

The spelling of 685801 in words is "six hundred eighty-five thousand, eight hundred one".