1217355221 has 2 divisors, whose sum is σ = 1217355222. Its totient is φ = 1217355220.

The previous prime is 1217355199. The next prime is 1217355253. The reversal of 1217355221 is 1225537121.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 991935025 + 225420196 = 31495^2 + 15014^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1217355221 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1217355281) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 608677610 + 608677611.

It is an arithmetic number, because the mean of its divisors is an integer number (608677611).

Almost surely, 2^1217355221 is an apocalyptic number.

It is an amenable number.

1217355221 is a deficient number, since it is larger than the sum of its proper divisors (1).

1217355221 is an equidigital number, since it uses as much as digits as its factorization.

1217355221 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 4200, while the sum is 29.

The square root of 1217355221 is about 34890.6179509621. The cubic root of 1217355221 is about 1067.7570335400.

The spelling of 1217355221 in words is "one billion, two hundred seventeen million, three hundred fifty-five thousand, two hundred twenty-one".