685261189 has 2 divisors, whose sum is σ = 685261190. Its totient is φ = 685261188.

The previous prime is 685261141. The next prime is 685261217. The reversal of 685261189 is 981162586.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 489736900 + 195524289 = 22130^2 + 13983^2 .

It is a cyclic number.

It is not a de Polignac number, because 685261189 - 2⁷ = 685261061 is a prime.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (685261289) 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 as a sum of consecutive naturals, namely, 342630594 + 342630595.

It is an arithmetic number, because the mean of its divisors is an integer number (342630595).

Almost surely, 2^685261189 is an apocalyptic number.

It is an amenable number.

685261189 is a deficient number, since it is larger than the sum of its proper divisors (1).

685261189 is an equidigital number, since it uses as much as digits as its factorization.

685261189 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 207360, while the sum is 46.

The square root of 685261189 is about 26177.4939404061. The cubic root of 685261189 is about 881.6280077500.

The spelling of 685261189 in words is "six hundred eighty-five million, two hundred sixty-one thousand, one hundred eighty-nine".