1291305221 has 2 divisors, whose sum is σ = 1291305222. Its totient is φ = 1291305220.

The previous prime is 1291305203. The next prime is 1291305247. The reversal of 1291305221 is 1225031921.

It is a happy number.

It is an a-pointer prime, because the next prime (1291305247) can be obtained adding 1291305221 to its sum of digits (26).

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 784560100 + 506745121 = 28010^2 + 22511^2 .

It is an emirp because it is prime and its reverse (1225031921) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 1291305221 - 2¹⁰ = 1291304197 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1291304221) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 645652610 + 645652611.

It is an arithmetic number, because the mean of its divisors is an integer number (645652611).

Almost surely, 2^1291305221 is an apocalyptic number.

It is an amenable number.

1291305221 is a deficient number, since it is larger than the sum of its proper divisors (1).

1291305221 is an equidigital number, since it uses as much as digits as its factorization.

1291305221 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 1080, while the sum is 26.

The square root of 1291305221 is about 35934.7355771543. The cubic root of 1291305221 is about 1088.9542536035.

The spelling of 1291305221 in words is "one billion, two hundred ninety-one million, three hundred five thousand, two hundred twenty-one".