1843780221 has 12 divisors (see below), whose sum is σ = 2663610300. Its totient is φ = 1229015040.

The previous prime is 1843780219. The next prime is 1843780229. The reversal of 1843780221 is 1220873481.

It can be written as a sum of positive squares in 2 ways, for example, as 1535777721 + 308002500 = 39189^2 + 17550^2 .

It is not a de Polignac number, because 1843780221 - 2¹ = 1843780219 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1843780229) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 119455 + ... + 134003.

It is an arithmetic number, because the mean of its divisors is an integer number (221967525).

Almost surely, 2^1843780221 is an apocalyptic number.

It is an amenable number.

1843780221 is a deficient number, since it is larger than the sum of its proper divisors (819830079).

1843780221 is a wasteful number, since it uses less digits than its factorization.

1843780221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 28636 (or 28633 counting only the distinct ones).

The product of its (nonzero) digits is 21504, while the sum is 36.

The square root of 1843780221 is about 42939.2619987815. The cubic root of 1843780221 is about 1226.2237325063.

The spelling of 1843780221 in words is "one billion, eight hundred forty-three million, seven hundred eighty thousand, two hundred twenty-one".