685631893 has 2 divisors, whose sum is σ = 685631894. Its totient is φ = 685631892.

The previous prime is 685631873. The next prime is 685631917. The reversal of 685631893 is 398136586.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 404130609 + 281501284 = 20103^2 + 16778^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-685631893 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (685631873) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 342815946 + 342815947.

It is an arithmetic number, because the mean of its divisors is an integer number (342815947).

Almost surely, 2^685631893 is an apocalyptic number.

It is an amenable number.

685631893 is a deficient number, since it is larger than the sum of its proper divisors (1).

685631893 is an equidigital number, since it uses as much as digits as its factorization.

685631893 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 933120, while the sum is 49.

The square root of 685631893 is about 26184.5735691838. The cubic root of 685631893 is about 881.7869564440.

The spelling of 685631893 in words is "six hundred eighty-five million, six hundred thirty-one thousand, eight hundred ninety-three".