687385813 has 4 divisors (see below), whose sum is σ = 699036480. Its totient is φ = 675735148.

The previous prime is 687385801. The next prime is 687385817. The reversal of 687385813 is 318583786.

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: 318583786 = 2 ⋅159291893.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-687385813 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 (687385817) 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, 5825245 + ... + 5825362.

It is an arithmetic number, because the mean of its divisors is an integer number (174759120).

Almost surely, 2^687385813 is an apocalyptic number.

It is an amenable number.

687385813 is a deficient number, since it is larger than the sum of its proper divisors (11650667).

687385813 is a wasteful number, since it uses less digits than its factorization.

687385813 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 11650666.

The product of its digits is 967680, while the sum is 49.

The square root of 687385813 is about 26218.0436531790. The cubic root of 687385813 is about 882.5382181096.

The spelling of 687385813 in words is "six hundred eighty-seven million, three hundred eighty-five thousand, eight hundred thirteen".