1806643 has 2 divisors, whose sum is σ = 1806644. Its totient is φ = 1806642.

The previous prime is 1806631. The next prime is 1806683. The reversal of 1806643 is 3466081.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 1806643 - 2¹³ = 1798451 is a prime.

It is not a weakly prime, because it can be changed into another prime (1806683) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 903321 + 903322.

It is an arithmetic number, because the mean of its divisors is an integer number (903322).

2^1806643 is an apocalyptic number.

1806643 is a deficient number, since it is larger than the sum of its proper divisors (1).

1806643 is an equidigital number, since it uses as much as digits as its factorization.

1806643 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 3456, while the sum is 28.

The square root of 1806643 is about 1344.1142064572. The cubic root of 1806643 is about 121.7935008931.

The spelling of 1806643 in words is "one million, eight hundred six thousand, six hundred forty-three".