685961 has 4 divisors (see below), whose sum is σ = 689424. Its totient is φ = 682500.

The previous prime is 685939. The next prime is 685963. The reversal of 685961 is 169586.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also an emirpimes, since its reverse is a distinct semiprime: 169586 = 2 ⋅84793.

It is a cyclic number.

It is not a de Polignac number, because 685961 - 2¹⁴ = 669577 is a prime.

It is a Duffinian number.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 685961.

It is not an unprimeable number, because it can be changed into a prime (685963) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1415 + ... + 1836.

It is an arithmetic number, because the mean of its divisors is an integer number (172356).

2⁶⁸⁵⁹⁶¹ is an apocalyptic number.

It is an amenable number.

685961 is a deficient number, since it is larger than the sum of its proper divisors (3463).

685961 is a wasteful number, since it uses less digits than its factorization.

685961 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3462.

The product of its digits is 12960, while the sum is 35.

The square root of 685961 is about 828.2276257165. The cubic root of 685961 is about 88.1928021371.

The spelling of 685961 in words is "six hundred eighty-five thousand, nine hundred sixty-one".