221305009 has 2 divisors, whose sum is σ = 221305010. Its totient is φ = 221305008.

The previous prime is 221304971. The next prime is 221305033. The reversal of 221305009 is 900503122.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 198951025 + 22353984 = 14105^2 + 4728^2 .

It is a cyclic number.

It is not a de Polignac number, because 221305009 - 2¹⁷ = 221173937 is a prime.

It is not a weakly prime, because it can be changed into another prime (221305109) 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, 110652504 + 110652505.

It is an arithmetic number, because the mean of its divisors is an integer number (110652505).

Almost surely, 2^221305009 is an apocalyptic number.

It is an amenable number.

221305009 is a deficient number, since it is larger than the sum of its proper divisors (1).

221305009 is an equidigital number, since it uses as much as digits as its factorization.

221305009 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 540, while the sum is 22.

The square root of 221305009 is about 14876.3237730294. The cubic root of 221305009 is about 604.8723715935.

It can be divided in two parts, 22 and 1305009, that added together give a palindrome (1305031).

The spelling of 221305009 in words is "two hundred twenty-one million, three hundred five thousand, nine".