1805641 has 2 divisors, whose sum is σ = 1805642. Its totient is φ = 1805640.

The previous prime is 1805633. The next prime is 1805651. The reversal of 1805641 is 1465081.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 1679616 + 126025 = 1296^2 + 355^2 .

It is an emirp because it is prime and its reverse (1465081) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 1805641 - 2³ = 1805633 is a prime.

It is equal to p₁₃₅₄₅₇ and since 1805641 and 135457 have the same sum of digits, it is a Honaker prime.

It is not a weakly prime, because it can be changed into another prime (1805651) 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, 902820 + 902821.

It is an arithmetic number, because the mean of its divisors is an integer number (902821).

2^1805641 is an apocalyptic number.

It is an amenable number.

1805641 is a deficient number, since it is larger than the sum of its proper divisors (1).

1805641 is an equidigital number, since it uses as much as digits as its factorization.

1805641 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 960, while the sum is 25.

The square root of 1805641 is about 1343.7414185772. The cubic root of 1805641 is about 121.7709803663.

The spelling of 1805641 in words is "one million, eight hundred five thousand, six hundred forty-one".