687943135685 has 8 divisors (see below), whose sum is σ = 889034206200. Its totient is φ = 508019546304.

The previous prime is 687943135681. The next prime is 687943135687. The reversal of 687943135685 is 586531349786.

It can be written as a sum of positive squares in 4 ways, for example, as 24462836836 + 663480298849 = 156406^2 + 814543^2 .

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

It is a cyclic number.

It is not a de Polignac number, because 687943135685 - 2² = 687943135681 is a prime.

It is a super-2 number, since 2×687943135685² (a number of 24 digits) contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (65), and also a Moran number because the ratio is a prime number: 10583740549 = 687943135685 / (6 + 8 + 7 + 9 + 4 + 3 + 1 + 3 + 5 + 6 + 8 + 5).

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (687943135681) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 5291870210 + ... + 5291870339.

It is an arithmetic number, because the mean of its divisors is an integer number (111129275775).

Almost surely, 2^687943135685 is an apocalyptic number.

687943135685 is a gapful number since it is divisible by the number (65) formed by its first and last digit.

It is an amenable number.

687943135685 is a deficient number, since it is larger than the sum of its proper divisors (201091070515).

687943135685 is a wasteful number, since it uses less digits than its factorization.

687943135685 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10583740567.

The product of its digits is 130636800, while the sum is 65.

The spelling of 687943135685 in words is "six hundred eighty-seven billion, nine hundred forty-three million, one hundred thirty-five thousand, six hundred eighty-five".