687779 has 2 divisors, whose sum is σ = 687780. Its totient is φ = 687778.

The previous prime is 687773. The next prime is 687787. The reversal of 687779 is 977786.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 687779 - 2⁸ = 687523 is a prime.

It is not a weakly prime, because it can be changed into another prime (687773) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 343889 + 343890.

It is an arithmetic number, because the mean of its divisors is an integer number (343890).

2⁶⁸⁷⁷⁷⁹ is an apocalyptic number.

687779 is a deficient number, since it is larger than the sum of its proper divisors (1).

687779 is an equidigital number, since it uses as much as digits as its factorization.

687779 is an evil number, because the sum of its binary digits is even.

The product of its digits is 148176, while the sum is 44.

The square root of 687779 is about 829.3244238535. The cubic root of 687779 is about 88.2706457647.

It can be divided in two parts, 68777 and 9, that added together give a palindrome (68786).

The spelling of 687779 in words is "six hundred eighty-seven thousand, seven hundred seventy-nine".