1668647 has 2 divisors, whose sum is σ = 1668648. Its totient is φ = 1668646.

The previous prime is 1668629. The next prime is 1668649. The reversal of 1668647 is 7468661.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 1668647 - 2¹⁰ = 1667623 is a prime.

Together with 1668649, it forms a pair of twin primes.

It is a Chen prime.

It is a self number, because there is not a number n which added to its sum of digits gives 1668647.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1668649) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 834323 + 834324.

It is an arithmetic number, because the mean of its divisors is an integer number (834324).

2^1668647 is an apocalyptic number.

1668647 is a deficient number, since it is larger than the sum of its proper divisors (1).

1668647 is an equidigital number, since it uses as much as digits as its factorization.

1668647 is an evil number, because the sum of its binary digits is even.

The product of its digits is 48384, while the sum is 38.

The square root of 1668647 is about 1291.7612008417. The cubic root of 1668647 is about 118.6100504589.

The spelling of 1668647 in words is "one million, six hundred sixty-eight thousand, six hundred forty-seven".