221051009 has 2 divisors, whose sum is σ = 221051010. Its totient is φ = 221051008.

The previous prime is 221050981. The next prime is 221051029. The reversal of 221051009 is 900150122.

It is an a-pointer prime, because the next prime (221051029) can be obtained adding 221051009 to its sum of digits (20).

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 127057984 + 93993025 = 11272^2 + 9695^2 .

It is a cyclic number.

It is not a de Polignac number, because 221051009 - 2¹⁶ = 220985473 is a prime.

It is not a weakly prime, because it can be changed into another prime (221051029) 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, 110525504 + 110525505.

It is an arithmetic number, because the mean of its divisors is an integer number (110525505).

Almost surely, 2^221051009 is an apocalyptic number.

It is an amenable number.

221051009 is a deficient number, since it is larger than the sum of its proper divisors (1).

221051009 is an equidigital number, since it uses as much as digits as its factorization.

221051009 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 180, while the sum is 20.

The square root of 221051009 is about 14867.7842666619. The cubic root of 221051009 is about 604.6408714886.

The spelling of 221051009 in words is "two hundred twenty-one million, fifty-one thousand, nine".