1680509 has 2 divisors, whose sum is σ = 1680510. Its totient is φ = 1680508.

The previous prime is 1680491. The next prime is 1680527. The reversal of 1680509 is 9050861.

It is a balanced prime because it is at equal distance from previous prime (1680491) and next prime (1680527).

It can be written as a sum of positive squares in only one way, i.e., 1452025 + 228484 = 1205^2 + 478^2 .

It is an emirp because it is prime and its reverse (9050861) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 1680509 - 2⁸ = 1680253 is a prime.

It is a super-2 number, since 2×1680509² = 5648220998162, which contains 22 as substring.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1680529) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 840254 + 840255.

It is an arithmetic number, because the mean of its divisors is an integer number (840255).

2^1680509 is an apocalyptic number.

It is an amenable number.

1680509 is a deficient number, since it is larger than the sum of its proper divisors (1).

1680509 is an equidigital number, since it uses as much as digits as its factorization.

1680509 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 2160, while the sum is 29.

The square root of 1680509 is about 1296.3444758242. The cubic root of 1680509 is about 118.8904436218.

The spelling of 1680509 in words is "one million, six hundred eighty thousand, five hundred nine".