1291680491 has 2 divisors, whose sum is σ = 1291680492. Its totient is φ = 1291680490.

The previous prime is 1291680479. The next prime is 1291680497. The reversal of 1291680491 is 1940861921.

It is a strong prime.

It is an emirp because it is prime and its reverse (1940861921) is a distict prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1291680491 is a prime.

It is not a weakly prime, because it can be changed into another prime (1291680497) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 645840245 + 645840246.

It is an arithmetic number, because the mean of its divisors is an integer number (645840246).

Almost surely, 2^1291680491 is an apocalyptic number.

1291680491 is a deficient number, since it is larger than the sum of its proper divisors (1).

1291680491 is an equidigital number, since it uses as much as digits as its factorization.

1291680491 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 31104, while the sum is 41.

The square root of 1291680491 is about 35939.9567473307. The cubic root of 1291680491 is about 1089.0597314502.

The spelling of 1291680491 in words is "one billion, two hundred ninety-one million, six hundred eighty thousand, four hundred ninety-one".