685687551 has 8 divisors (see below), whose sum is σ = 917727360. Its totient is φ = 455386392.

The previous prime is 685687501. The next prime is 685687591. The reversal of 685687551 is 155786586.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 685687551 - 2⁷ = 685687423 is a prime.

It is a Smith number, since the sum of its digits (51) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a junction number, because it is equal to n+sod(n) for n = 685687494 and 685687503.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (685687501) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 433741 + ... + 435318.

It is an arithmetic number, because the mean of its divisors is an integer number (114715920).

Almost surely, 2^685687551 is an apocalyptic number.

685687551 is a deficient number, since it is larger than the sum of its proper divisors (232039809).

685687551 is a wasteful number, since it uses less digits than its factorization.

685687551 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 869325.

The product of its digits is 2016000, while the sum is 51.

The square root of 685687551 is about 26185.6363489605. The cubic root of 685687551 is about 881.8108162687.

The spelling of 685687551 in words is "six hundred eighty-five million, six hundred eighty-seven thousand, five hundred fifty-one".