221221231009 has 2 divisors, whose sum is σ = 221221231010. Its totient is φ = 221221231008.

The previous prime is 221221230949. The next prime is 221221231027. The reversal of 221221231009 is 900132122122.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 220996830609 + 224400400 = 470103^2 + 14980^2 .

It is a cyclic number.

It is not a de Polignac number, because 221221231009 - 2¹¹ = 221221228961 is a prime.

It is not a weakly prime, because it can be changed into another prime (221221231109) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 110610615504 + 110610615505.

It is an arithmetic number, because the mean of its divisors is an integer number (110610615505).

Almost surely, 2^221221231009 is an apocalyptic number.

It is an amenable number.

221221231009 is a deficient number, since it is larger than the sum of its proper divisors (1).

221221231009 is an equidigital number, since it uses as much as digits as its factorization.

221221231009 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 864, while the sum is 25.

The spelling of 221221231009 in words is "two hundred twenty-one billion, two hundred twenty-one million, two hundred thirty-one thousand, nine".