685931243 has 2 divisors, whose sum is σ = 685931244. Its totient is φ = 685931242.

The previous prime is 685931161. The next prime is 685931261. The reversal of 685931243 is 342139586.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-685931243 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 685931243.

It is not a weakly prime, because it can be changed into another prime (685931143) 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, 342965621 + 342965622.

It is an arithmetic number, because the mean of its divisors is an integer number (342965622).

Almost surely, 2^685931243 is an apocalyptic number.

685931243 is a deficient number, since it is larger than the sum of its proper divisors (1).

685931243 is an equidigital number, since it uses as much as digits as its factorization.

685931243 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 155520, while the sum is 41.

The square root of 685931243 is about 26190.2890972971. The cubic root of 685931243 is about 881.9152685026.

The spelling of 685931243 in words is "six hundred eighty-five million, nine hundred thirty-one thousand, two hundred forty-three".