1291049491 has 2 divisors, whose sum is σ = 1291049492. Its totient is φ = 1291049490.

The previous prime is 1291049489. The next prime is 1291049497. The reversal of 1291049491 is 1949401921.

It is a weak prime.

It is an emirp because it is prime and its reverse (1949401921) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 1291049491 - 2¹ = 1291049489 is a prime.

It is a super-3 number, since 3×1291049491³ (a number of 28 digits) contains 333 as substring. Note that it is a super-d number also for d = 2.

Together with 1291049489, it forms a pair of twin primes.

It is not a weakly prime, because it can be changed into another prime (1291049497) 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, 645524745 + 645524746.

It is an arithmetic number, because the mean of its divisors is an integer number (645524746).

Almost surely, 2^1291049491 is an apocalyptic number.

1291049491 is a deficient number, since it is larger than the sum of its proper divisors (1).

1291049491 is an equidigital number, since it uses as much as digits as its factorization.

1291049491 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 23328, while the sum is 40.

The square root of 1291049491 is about 35931.1771446470. The cubic root of 1291049491 is about 1088.8823633816.

The spelling of 1291049491 in words is "one billion, two hundred ninety-one million, forty-nine thousand, four hundred ninety-one".