1291252321 has 2 divisors, whose sum is σ = 1291252322. Its totient is φ = 1291252320.

The previous prime is 1291252297. The next prime is 1291252337. The reversal of 1291252321 is 1232521921.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1260605025 + 30647296 = 35505^2 + 5536^2 .

It is a cyclic number.

It is not a de Polignac number, because 1291252321 - 2¹¹ = 1291250273 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 1291252321.

It is not a weakly prime, because it can be changed into another prime (1291250321) 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, 645626160 + 645626161.

It is an arithmetic number, because the mean of its divisors is an integer number (645626161).

Almost surely, 2^1291252321 is an apocalyptic number.

It is an amenable number.

1291252321 is a deficient number, since it is larger than the sum of its proper divisors (1).

1291252321 is an equidigital number, since it uses as much as digits as its factorization.

1291252321 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 2160, while the sum is 28.

The square root of 1291252321 is about 35933.9995129960. Note that the first 3 decimals coincide. The cubic root of 1291252321 is about 1088.9393832574.

The spelling of 1291252321 in words is "one billion, two hundred ninety-one million, two hundred fifty-two thousand, three hundred twenty-one".