1805340221 has 4 divisors (see below), whose sum is σ = 1827091392. Its totient is φ = 1783589052.

The previous prime is 1805340197. The next prime is 1805340239. The reversal of 1805340221 is 1220435081.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 1805340221 - 2¹⁰ = 1805339197 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1805340281) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 10875461 + ... + 10875626.

It is an arithmetic number, because the mean of its divisors is an integer number (456772848).

Almost surely, 2^1805340221 is an apocalyptic number.

It is an amenable number.

1805340221 is a deficient number, since it is larger than the sum of its proper divisors (21751171).

1805340221 is an equidigital number, since it uses as much as digits as its factorization.

1805340221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 21751170.

The product of its (nonzero) digits is 1920, while the sum is 26.

The square root of 1805340221 is about 42489.2953695398. The cubic root of 1805340221 is about 1217.6421855932.

The spelling of 1805340221 in words is "one billion, eight hundred five million, three hundred forty thousand, two hundred twenty-one".