685931161 has 2 divisors, whose sum is σ = 685931162. Its totient is φ = 685931160.

The previous prime is 685931159. The next prime is 685931243. The reversal of 685931161 is 161139586.

685931161 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 589518400 + 96412761 = 24280^2 + 9819^2 .

It is a cyclic number.

It is not a de Polignac number, because 685931161 - 2¹ = 685931159 is a prime.

Together with 685931159, it forms a pair of twin primes.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (685931101) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 342965580 + 342965581.

It is an arithmetic number, because the mean of its divisors is an integer number (342965581).

Almost surely, 2^685931161 is an apocalyptic number.

It is an amenable number.

685931161 is a deficient number, since it is larger than the sum of its proper divisors (1).

685931161 is an equidigital number, since it uses as much as digits as its factorization.

685931161 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 38880, while the sum is 40.

The square root of 685931161 is about 26190.2875318313. The cubic root of 685931161 is about 881.9152333596.

The spelling of 685931161 in words is "six hundred eighty-five million, nine hundred thirty-one thousand, one hundred sixty-one".