1687428909 has 16 divisors (see below), whose sum is σ = 2540879040. Its totient is φ = 1106509680.

The previous prime is 1687428889. The next prime is 1687428937. The reversal of 1687428909 is 9098247861.

It is not a de Polignac number, because 1687428909 - 2⁹ = 1687428397 is a prime.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1687420909) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 510627 + ... + 513920.

It is an arithmetic number, because the mean of its divisors is an integer number (158804940).

Almost surely, 2^1687428909 is an apocalyptic number.

It is an amenable number.

1687428909 is a deficient number, since it is larger than the sum of its proper divisors (853450131).

1687428909 is a wasteful number, since it uses less digits than its factorization.

1687428909 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1024617 (or 1024611 counting only the distinct ones).

The product of its (nonzero) digits is 1741824, while the sum is 54.

The square root of 1687428909 is about 41078.3265116777. The cubic root of 1687428909 is about 1190.5340702335.

The spelling of 1687428909 in words is "one billion, six hundred eighty-seven million, four hundred twenty-eight thousand, nine hundred nine".