1266805091 has 2 divisors, whose sum is σ = 1266805092. Its totient is φ = 1266805090.

The previous prime is 1266805087. The next prime is 1266805097. The reversal of 1266805091 is 1905086621.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 1266805091 - 2² = 1266805087 is a prime.

It is not a weakly prime, because it can be changed into another prime (1266805097) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 633402545 + 633402546.

It is an arithmetic number, because the mean of its divisors is an integer number (633402546).

Almost surely, 2^1266805091 is an apocalyptic number.

1266805091 is a deficient number, since it is larger than the sum of its proper divisors (1).

1266805091 is an equidigital number, since it uses as much as digits as its factorization.

1266805091 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 25920, while the sum is 38.

The square root of 1266805091 is about 35592.2054809757. The cubic root of 1266805091 is about 1082.0232680070.

The spelling of 1266805091 in words is "one billion, two hundred sixty-six million, eight hundred five thousand, ninety-one".