685889806709 has 4 divisors (see below), whose sum is σ = 721989270240. Its totient is φ = 649790343180.

The previous prime is 685889806703. The next prime is 685889806727. The reversal of 685889806709 is 907608988586.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also an emirpimes, since its reverse is a distinct semiprime: 907608988586 = 2 ⋅453804494293.

It is a cyclic number.

It is not a de Polignac number, because 685889806709 - 2⁸ = 685889806453 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (685889806703) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 18049731737 + ... + 18049731774.

It is an arithmetic number, because the mean of its divisors is an integer number (180497317560).

Almost surely, 2^685889806709 is an apocalyptic number.

It is an amenable number.

685889806709 is a deficient number, since it is larger than the sum of its proper divisors (36099463531).

685889806709 is a wasteful number, since it uses less digits than its factorization.

685889806709 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 36099463530.

The product of its (nonzero) digits is 418037760, while the sum is 74.

The spelling of 685889806709 in words is "six hundred eighty-five billion, eight hundred eighty-nine million, eight hundred six thousand, seven hundred nine".