685499994661 has 2 divisors, whose sum is σ = 685499994662. Its totient is φ = 685499994660.

The previous prime is 685499994527. The next prime is 685499994677. The reversal of 685499994661 is 166499994586.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 392690222500 + 292809772161 = 626650^2 + 541119^2 .

It is a cyclic number.

It is not a de Polignac number, because 685499994661 - 2⁹ = 685499994149 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (685499994161) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 342749997330 + 342749997331.

It is an arithmetic number, because the mean of its divisors is an integer number (342749997331).

Almost surely, 2^685499994661 is an apocalyptic number.

It is an amenable number.

685499994661 is a deficient number, since it is larger than the sum of its proper divisors (1).

685499994661 is an equidigital number, since it uses as much as digits as its factorization.

685499994661 is an evil number, because the sum of its binary digits is even.

The product of its digits is 906992640, while the sum is 76.

The spelling of 685499994661 in words is "six hundred eighty-five billion, four hundred ninety-nine million, nine hundred ninety-four thousand, six hundred sixty-one".