1291345491 has 8 divisors (see below), whose sum is σ = 1722270160. Its totient is φ = 860658912.

The previous prime is 1291345487. The next prime is 1291345493. The reversal of 1291345491 is 1945431921.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 1291345491 - 2² = 1291345487 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1291345493) 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 in 7 ways as a sum of consecutive naturals, for example, 46456 + ... + 68853.

It is an arithmetic number, because the mean of its divisors is an integer number (215283770).

Almost surely, 2^1291345491 is an apocalyptic number.

1291345491 is a deficient number, since it is larger than the sum of its proper divisors (430924669).

1291345491 is a wasteful number, since it uses less digits than its factorization.

1291345491 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 119045.

The product of its digits is 38880, while the sum is 39.

The square root of 1291345491 is about 35935.2958941484. The cubic root of 1291345491 is about 1088.9655733471.

It can be divided in two parts, 129 and 1345491, that added together give a triangular number (1345620 = T₁₆₄₀).

The spelling of 1291345491 in words is "one billion, two hundred ninety-one million, three hundred forty-five thousand, four hundred ninety-one".