1821081205 has 16 divisors (see below), whose sum is σ = 2257113600. Its totient is φ = 1409042880.

The previous prime is 1821081181. The next prime is 1821081217. The reversal of 1821081205 is 5021801281.

It is not a de Polignac number, because 1821081205 - 2¹³ = 1821073013 is a prime.

It is a congruent number.

It is an unprimeable number.

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 15 ways as a sum of consecutive naturals, for example, 480006 + ... + 483784.

It is an arithmetic number, because the mean of its divisors is an integer number (141069600).

Almost surely, 2^1821081205 is an apocalyptic number.

It is an amenable number.

1821081205 is a deficient number, since it is larger than the sum of its proper divisors (436032395).

1821081205 is a wasteful number, since it uses less digits than its factorization.

1821081205 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6924.

The product of its (nonzero) digits is 1280, while the sum is 28.

The square root of 1821081205 is about 42674.1280520177. The cubic root of 1821081205 is about 1221.1708738095.

Adding to 1821081205 its reverse (5021801281), we get a palindrome (6842882486).

The spelling of 1821081205 in words is "one billion, eight hundred twenty-one million, eighty-one thousand, two hundred five".