1291304221 has 2 divisors, whose sum is σ = 1291304222. Its totient is φ = 1291304220.

The previous prime is 1291304197. The next prime is 1291304279. The reversal of 1291304221 is 1224031921.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 1081488996 + 209815225 = 32886^2 + 14485^2 .

It is a cyclic number.

It is not a de Polignac number, because 1291304221 - 2²⁷ = 1157086493 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1291305221) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 645652110 + 645652111.

It is an arithmetic number, because the mean of its divisors is an integer number (645652111).

Almost surely, 2^1291304221 is an apocalyptic number.

It is an amenable number.

1291304221 is a deficient number, since it is larger than the sum of its proper divisors (1).

1291304221 is an equidigital number, since it uses as much as digits as its factorization.

1291304221 is an evil number, because the sum of its binary digits is even.

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

The square root of 1291304221 is about 35934.7216630378. The cubic root of 1291304221 is about 1088.9539725043.

The spelling of 1291304221 in words is "one billion, two hundred ninety-one million, three hundred four thousand, two hundred twenty-one".