687807749 has 2 divisors, whose sum is σ = 687807750. Its totient is φ = 687807748.

The previous prime is 687807727. The next prime is 687807751. The reversal of 687807749 is 947708786.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 604815649 + 82992100 = 24593^2 + 9110^2 .

It is a cyclic number.

It is not a de Polignac number, because 687807749 - 2¹⁶ = 687742213 is a prime.

It is a Sophie Germain prime.

Together with 687807751, it forms a pair of twin primes.

It is a Chen prime.

It is a Curzon number.

It is a junction number, because it is equal to n+sod(n) for n = 687807694 and 687807703.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (687807149) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 343903874 + 343903875.

It is an arithmetic number, because the mean of its divisors is an integer number (343903875).

Almost surely, 2^687807749 is an apocalyptic number.

It is an amenable number.

687807749 is a deficient number, since it is larger than the sum of its proper divisors (1).

687807749 is an equidigital number, since it uses as much as digits as its factorization.

687807749 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 4741632, while the sum is 56.

The square root of 687807749 is about 26226.0890908271. The cubic root of 687807749 is about 882.7187564494.

The spelling of 687807749 in words is "six hundred eighty-seven million, eight hundred seven thousand, seven hundred forty-nine".