686871509 has 8 divisors (see below), whose sum is σ = 691441920. Its totient is φ = 682309600.

The previous prime is 686871487. The next prime is 686871541. The reversal of 686871509 is 905178686.

It is a happy number.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-686871509 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (686871599) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 263804 + ... + 266394.

It is an arithmetic number, because the mean of its divisors is an integer number (86430240).

Almost surely, 2^686871509 is an apocalyptic number.

It is an amenable number.

686871509 is a deficient number, since it is larger than the sum of its proper divisors (4570411).

686871509 is a wasteful number, since it uses less digits than its factorization.

686871509 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4251.

The product of its (nonzero) digits is 725760, while the sum is 50.

The square root of 686871509 is about 26208.2336108331. The cubic root of 686871509 is about 882.3180573326.

The spelling of 686871509 in words is "six hundred eighty-six million, eight hundred seventy-one thousand, five hundred nine".