685566613 has 2 divisors, whose sum is σ = 685566614. Its totient is φ = 685566612.

The previous prime is 685566533. The next prime is 685566653. The reversal of 685566613 is 316665586.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 369331524 + 316235089 = 19218^2 + 17783^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-685566613 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (685566653) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 342783306 + 342783307.

It is an arithmetic number, because the mean of its divisors is an integer number (342783307).

Almost surely, 2^685566613 is an apocalyptic number.

It is an amenable number.

685566613 is a deficient number, since it is larger than the sum of its proper divisors (1).

685566613 is an equidigital number, since it uses as much as digits as its factorization.

685566613 is an evil number, because the sum of its binary digits is even.

The product of its digits is 777600, while the sum is 46.

The square root of 685566613 is about 26183.3270040306. The cubic root of 685566613 is about 881.7589701537.

The spelling of 685566613 in words is "six hundred eighty-five million, five hundred sixty-six thousand, six hundred thirteen".