1687643 has 2 divisors, whose sum is σ = 1687644. Its totient is φ = 1687642.

The previous prime is 1687633. The next prime is 1687657. The reversal of 1687643 is 3467861.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 1687643 - 2⁴ = 1687627 is a prime.

It is a Sophie Germain prime.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (1687603) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 843821 + 843822.

It is an arithmetic number, because the mean of its divisors is an integer number (843822).

2^1687643 is an apocalyptic number.

1687643 is a deficient number, since it is larger than the sum of its proper divisors (1).

1687643 is an equidigital number, since it uses as much as digits as its factorization.

1687643 is an evil number, because the sum of its binary digits is even.

The product of its digits is 24192, while the sum is 35.

The square root of 1687643 is about 1299.0931452363. The cubic root of 1687643 is about 119.0584417412.

The spelling of 1687643 in words is "one million, six hundred eighty-seven thousand, six hundred forty-three".