686969009 has 4 divisors (see below), whose sum is σ = 687753204. Its totient is φ = 686184816.

The previous prime is 686968999. The next prime is 686969027. The reversal of 686969009 is 900969686.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 427662400 + 259306609 = 20680^2 + 16103^2 .

It is a cyclic number.

It is not a de Polignac number, because 686969009 - 2⁴ = 686968993 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (686969039) by changing a digit.

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, 390782 + ... + 392535.

It is an arithmetic number, because the mean of its divisors is an integer number (171938301).

Almost surely, 2^686969009 is an apocalyptic number.

It is an amenable number.

686969009 is a deficient number, since it is larger than the sum of its proper divisors (784195).

686969009 is an equidigital number, since it uses as much as digits as its factorization.

686969009 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 784194.

The product of its (nonzero) digits is 1259712, while the sum is 53.

The square root of 686969009 is about 26210.0936472955. The cubic root of 686969009 is about 882.3598031028.

The spelling of 686969009 in words is "six hundred eighty-six million, nine hundred sixty-nine thousand, nine".