1291321 has 2 divisors, whose sum is σ = 1291322. Its totient is φ = 1291320.

The previous prime is 1291313. The next prime is 1291327. The reversal of 1291321 is 1231921.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 881721 + 409600 = 939^2 + 640^2 .

It is a cyclic number.

It is not a de Polignac number, because 1291321 - 2³ = 1291313 is a prime.

It is not a weakly prime, because it can be changed into another prime (1291327) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 645660 + 645661.

It is an arithmetic number, because the mean of its divisors is an integer number (645661).

2^1291321 is an apocalyptic number.

It is an amenable number.

1291321 is a deficient number, since it is larger than the sum of its proper divisors (1).

1291321 is an equidigital number, since it uses as much as digits as its factorization.

1291321 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 108, while the sum is 19.

The square root of 1291321 is about 1136.3630581817. The cubic root of 1291321 is about 108.8958689048.

The spelling of 1291321 in words is "one million, two hundred ninety-one thousand, three hundred twenty-one".