1281090491 has 2 divisors, whose sum is σ = 1281090492. Its totient is φ = 1281090490.

The previous prime is 1281090439. The next prime is 1281090571. The reversal of 1281090491 is 1940901821.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 1281090491 - 2⁶ = 1281090427 is a prime.

It is a super-2 number, since 2×1281090491² = 3282385692261242162, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (1281590491) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 640545245 + 640545246.

It is an arithmetic number, because the mean of its divisors is an integer number (640545246).

Almost surely, 2^1281090491 is an apocalyptic number.

1281090491 is a deficient number, since it is larger than the sum of its proper divisors (1).

1281090491 is an equidigital number, since it uses as much as digits as its factorization.

1281090491 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 5184, while the sum is 35.

The square root of 1281090491 is about 35792.3244704783. The cubic root of 1281090491 is about 1086.0752974482.

It can be divided in two parts, 12810 and 90491, that added together give a palindrome (103301).

The spelling of 1281090491 in words is "one billion, two hundred eighty-one million, ninety thousand, four hundred ninety-one".