1291428889 has 2 divisors, whose sum is σ = 1291428890. Its totient is φ = 1291428888.

The previous prime is 1291428881. The next prime is 1291428937. The reversal of 1291428889 is 9888241921.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 669774400 + 621654489 = 25880^2 + 24933^2 .

It is an emirp because it is prime and its reverse (9888241921) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 1291428889 - 2³ = 1291428881 is a prime.

It is not a weakly prime, because it can be changed into another prime (1291428881) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 645714444 + 645714445.

It is an arithmetic number, because the mean of its divisors is an integer number (645714445).

Almost surely, 2^1291428889 is an apocalyptic number.

It is an amenable number.

1291428889 is a deficient number, since it is larger than the sum of its proper divisors (1).

1291428889 is an equidigital number, since it uses as much as digits as its factorization.

1291428889 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 663552, while the sum is 52.

The square root of 1291428889 is about 35936.4562665825. The cubic root of 1291428889 is about 1088.9890154588.

The spelling of 1291428889 in words is "one billion, two hundred ninety-one million, four hundred twenty-eight thousand, eight hundred eighty-nine".