1805261 has 2 divisors, whose sum is σ = 1805262. Its totient is φ = 1805260.

The previous prime is 1805239. The next prime is 1805263. The reversal of 1805261 is 1625081.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1155625 + 649636 = 1075^2 + 806^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1805261 is a prime.

Together with 1805263, it forms a pair of twin primes.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1805263) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 902630 + 902631.

It is an arithmetic number, because the mean of its divisors is an integer number (902631).

2^1805261 is an apocalyptic number.

It is an amenable number.

1805261 is a deficient number, since it is larger than the sum of its proper divisors (1).

1805261 is an equidigital number, since it uses as much as digits as its factorization.

1805261 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 480, while the sum is 23.

The square root of 1805261 is about 1343.6000148854. The cubic root of 1805261 is about 121.7624374686.

The spelling of 1805261 in words is "one million, eight hundred five thousand, two hundred sixty-one".