685906722 has 18 divisors (see below), whose sum is σ = 1486372017. Its totient is φ = 228598536.

The previous prime is 685906721. The next prime is 685906733. The reversal of 685906722 is 227609586.

It can be written as a sum of positive squares in 2 ways, for example, as 404371881 + 281534841 = 20109^2 + 16779^2 .

It is a tau number, because it is divible by the number of its divisors (18).

It is an ABA number since it can be written as A⋅B^A, here for A=2, B=18519.

It is not an unprimeable number, because it can be changed into a prime (685906721) by changing a digit.

It is a polite number, since it can be written in 8 ways as a sum of consecutive naturals, for example, 108028 + ... + 114200.

Almost surely, 2^685906722 is an apocalyptic number.

685906722 is an abundant number, since it is smaller than the sum of its proper divisors (800465295).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

685906722 is an frugal number, since it uses more digits than its factorization.

685906722 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 12354 (or 6178 counting only the distinct ones).

The product of its (nonzero) digits is 362880, while the sum is 45.

The square root of 685906722 is about 26189.8209615873. The cubic root of 685906722 is about 881.9047593336.

The spelling of 685906722 in words is "six hundred eighty-five million, nine hundred six thousand, seven hundred twenty-two".