221221200509 has 2 divisors, whose sum is σ = 221221200510. Its totient is φ = 221221200508.

The previous prime is 221221200427. The next prime is 221221200523. The reversal of 221221200509 is 905002122122.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 167977022500 + 53244178009 = 409850^2 + 230747^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-221221200509 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (221221200709) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 110610600254 + 110610600255.

It is an arithmetic number, because the mean of its divisors is an integer number (110610600255).

Almost surely, 2^221221200509 is an apocalyptic number.

It is an amenable number.

221221200509 is a deficient number, since it is larger than the sum of its proper divisors (1).

221221200509 is an equidigital number, since it uses as much as digits as its factorization.

221221200509 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 1440, while the sum is 26.

The spelling of 221221200509 in words is "two hundred twenty-one billion, two hundred twenty-one million, two hundred thousand, five hundred nine".