685917761 has 4 divisors (see below), whose sum is σ = 687172272. Its totient is φ = 684663252.

The previous prime is 685917731. The next prime is 685917767. The reversal of 685917761 is 167719586.

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.

It is a cyclic number.

It is not a de Polignac number, because 685917761 - 2²² = 681723457 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (685917767) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 626435 + ... + 627528.

It is an arithmetic number, because the mean of its divisors is an integer number (171793068).

Almost surely, 2^685917761 is an apocalyptic number.

It is an amenable number.

685917761 is a deficient number, since it is larger than the sum of its proper divisors (1254511).

685917761 is a wasteful number, since it uses less digits than its factorization.

685917761 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1254510.

The product of its digits is 635040, while the sum is 50.

The square root of 685917761 is about 26190.0317105574. The cubic root of 685917761 is about 881.9094904407.

The spelling of 685917761 in words is "six hundred eighty-five million, nine hundred seventeen thousand, seven hundred sixty-one".