1806491 has 2 divisors, whose sum is σ = 1806492. Its totient is φ = 1806490.

The previous prime is 1806487. The next prime is 1806499. The reversal of 1806491 is 1946081.

It is a weak prime.

It is an emirp because it is prime and its reverse (1946081) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 1806491 - 2² = 1806487 is a prime.

It is not a weakly prime, because it can be changed into another prime (1806499) 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, 903245 + 903246.

It is an arithmetic number, because the mean of its divisors is an integer number (903246).

2^1806491 is an apocalyptic number.

1806491 is a deficient number, since it is larger than the sum of its proper divisors (1).

1806491 is an equidigital number, since it uses as much as digits as its factorization.

1806491 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 1728, while the sum is 29.

The square root of 1806491 is about 1344.0576624535. The cubic root of 1806491 is about 121.7900851414.

The spelling of 1806491 in words is "one million, eight hundred six thousand, four hundred ninety-one".