687686786 has 8 divisors (see below), whose sum is σ = 1031701644. Its totient is φ = 343786240.

The previous prime is 687686743. The next prime is 687686807.

687686786 is nontrivially palindromic in base 10.

It can be written as a sum of positive squares in 2 ways, for example, as 679592761 + 8094025 = 26069^2 + 2845^2 .

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

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 11495 + ... + 38826.

Almost surely, 2^687686786 is an apocalyptic number.

687686786 is a deficient number, since it is larger than the sum of its proper divisors (344014858).

687686786 is a wasteful number, since it uses less digits than its factorization.

687686786 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 57156.

The product of its digits is 32514048, while the sum is 62.

The square root of 687686786 is about 26223.7828316206. The cubic root of 687686786 is about 882.6670062478.

The spelling of 687686786 in words is "six hundred eighty-seven million, six hundred eighty-six thousand, seven hundred eighty-six".