685800013 has 2 divisors, whose sum is σ = 685800014. Its totient is φ = 685800012.

The previous prime is 685800001. The next prime is 685800023. The reversal of 685800013 is 310008586.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 565393284 + 120406729 = 23778^2 + 10973^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-685800013 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (685800023) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 342900006 + 342900007.

It is an arithmetic number, because the mean of its divisors is an integer number (342900007).

Almost surely, 2^685800013 is an apocalyptic number.

It is an amenable number.

685800013 is a deficient number, since it is larger than the sum of its proper divisors (1).

685800013 is an equidigital number, since it uses as much as digits as its factorization.

685800013 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 5760, while the sum is 31.

The square root of 685800013 is about 26187.7836595616. The cubic root of 685800013 is about 881.8590232529.

Adding to 685800013 its reverse (310008586), we get a palindrome (995808599).

The spelling of 685800013 in words is "six hundred eighty-five million, eight hundred thousand, thirteen".