221323209509 has 2 divisors, whose sum is σ = 221323209510. Its totient is φ = 221323209508.

The previous prime is 221323209493. The next prime is 221323209511. The reversal of 221323209509 is 905902323122.

221323209509 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 111407753284 + 109915456225 = 333778^2 + 331535^2 .

It is a cyclic number.

It is not a de Polignac number, because 221323209509 - 2⁴ = 221323209493 is a prime.

Together with 221323209511, it forms a pair of twin primes.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (221323209599) by changing a digit.

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 as a sum of consecutive naturals, namely, 110661604754 + 110661604755.

It is an arithmetic number, because the mean of its divisors is an integer number (110661604755).

Almost surely, 2^221323209509 is an apocalyptic number.

It is an amenable number.

221323209509 is a deficient number, since it is larger than the sum of its proper divisors (1).

221323209509 is an equidigital number, since it uses as much as digits as its factorization.

221323209509 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 58320, while the sum is 38.

The spelling of 221323209509 in words is "two hundred twenty-one billion, three hundred twenty-three million, two hundred nine thousand, five hundred nine".