687675217 has 2 divisors, whose sum is σ = 687675218. Its totient is φ = 687675216.

The previous prime is 687675193. The next prime is 687675239. The reversal of 687675217 is 712576786.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 631064641 + 56610576 = 25121^2 + 7524^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-687675217 is a prime.

It is not a weakly prime, because it can be changed into another prime (687675017) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 343837608 + 343837609.

It is an arithmetic number, because the mean of its divisors is an integer number (343837609).

Almost surely, 2^687675217 is an apocalyptic number.

It is an amenable number.

687675217 is a deficient number, since it is larger than the sum of its proper divisors (1).

687675217 is an equidigital number, since it uses as much as digits as its factorization.

687675217 is an evil number, because the sum of its binary digits is even.

The product of its digits is 987840, while the sum is 49.

The square root of 687675217 is about 26223.5622484818. The cubic root of 687675217 is about 882.6620564983.

It can be divided in two parts, 68767 and 5217, that added together give a square (73984 = 272²).

The spelling of 687675217 in words is "six hundred eighty-seven million, six hundred seventy-five thousand, two hundred seventeen".