1291291289 has 2 divisors, whose sum is σ = 1291291290. Its totient is φ = 1291291288.

The previous prime is 1291291283. The next prime is 1291291291. The reversal of 1291291289 is 9821921921.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 739840000 + 551451289 = 27200^2 + 23483^2 .

It is a cyclic number.

It is not a de Polignac number, because 1291291289 - 2¹⁶ = 1291225753 is a prime.

Together with 1291291291, it forms a pair of twin primes.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (1291291283) 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, 645645644 + 645645645.

It is an arithmetic number, because the mean of its divisors is an integer number (645645645).

Almost surely, 2^1291291289 is an apocalyptic number.

It is an amenable number.

1291291289 is a deficient number, since it is larger than the sum of its proper divisors (1).

1291291289 is an equidigital number, since it uses as much as digits as its factorization.

1291291289 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 46656, while the sum is 44.

The square root of 1291291289 is about 35934.5417251981. The cubic root of 1291291289 is about 1088.9503373166.

The spelling of 1291291289 in words is "one billion, two hundred ninety-one million, two hundred ninety-one thousand, two hundred eighty-nine".