687685807 has 4 divisors (see below), whose sum is σ = 687913096. Its totient is φ = 687458520.

The previous prime is 687685771. The next prime is 687685841. The reversal of 687685807 is 708586786.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-687685807 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 (687685877) 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, 109044 + ... + 115177.

It is an arithmetic number, because the mean of its divisors is an integer number (171978274).

Almost surely, 2^687685807 is an apocalyptic number.

687685807 is a deficient number, since it is larger than the sum of its proper divisors (227289).

687685807 is a wasteful number, since it uses less digits than its factorization.

687685807 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 227288.

The product of its (nonzero) digits is 4515840, while the sum is 55.

The square root of 687685807 is about 26223.7641653520. The cubic root of 687685807 is about 882.6665873888. Note that the first 3 decimals are identical.

The spelling of 687685807 in words is "six hundred eighty-seven million, six hundred eighty-five thousand, eight hundred seven".