221301805 has 12 divisors (see below), whose sum is σ = 272301372. Its totient is φ = 172557120.

The previous prime is 221301781. The next prime is 221301809. The reversal of 221301805 is 508103122.

It can be written as a sum of positive squares in 2 ways, for example, as 38862756 + 182439049 = 6234^2 + 13507^2 .

It is not a de Polignac number, because 221301805 - 2⁹ = 221301293 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 (221301809) 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 in 11 ways as a sum of consecutive naturals, for example, 212476 + ... + 213514.

It is an arithmetic number, because the mean of its divisors is an integer number (22691781).

Almost surely, 2^221301805 is an apocalyptic number.

It is an amenable number.

221301805 is a deficient number, since it is larger than the sum of its proper divisors (50999567).

221301805 is an frugal number, since it uses more digits than its factorization.

221301805 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2124 (or 1085 counting only the distinct ones).

The product of its (nonzero) digits is 480, while the sum is 22.

The square root of 221301805 is about 14876.2160847441. The cubic root of 221301805 is about 604.8694525145.

Adding to 221301805 its reverse (508103122), we get a palindrome (729404927).

The spelling of 221301805 in words is "two hundred twenty-one million, three hundred one thousand, eight hundred five".