687316639 has 2 divisors, whose sum is σ = 687316640. Its totient is φ = 687316638.

The previous prime is 687316633. The next prime is 687316657. The reversal of 687316639 is 936613786.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 687316639 - 2⁵ = 687316607 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 687316592 and 687316601.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (687316633) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 343658319 + 343658320.

It is an arithmetic number, because the mean of its divisors is an integer number (343658320).

Almost surely, 2^687316639 is an apocalyptic number.

687316639 is a deficient number, since it is larger than the sum of its proper divisors (1).

687316639 is an equidigital number, since it uses as much as digits as its factorization.

687316639 is an evil number, because the sum of its binary digits is even.

The product of its digits is 979776, while the sum is 49.

The square root of 687316639 is about 26216.7244140072. The cubic root of 687316639 is about 882.5086128305.

The spelling of 687316639 in words is "six hundred eighty-seven million, three hundred sixteen thousand, six hundred thirty-nine".