1266303991 has 2 divisors, whose sum is σ = 1266303992. Its totient is φ = 1266303990.

The previous prime is 1266303971. The next prime is 1266304003. The reversal of 1266303991 is 1993036621.

It is a strong prime.

It is an emirp because it is prime and its reverse (1993036621) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 1266303991 - 2⁵ = 1266303959 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1266303971) 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, 633151995 + 633151996.

It is an arithmetic number, because the mean of its divisors is an integer number (633151996).

Almost surely, 2^1266303991 is an apocalyptic number.

1266303991 is a deficient number, since it is larger than the sum of its proper divisors (1).

1266303991 is an equidigital number, since it uses as much as digits as its factorization.

1266303991 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 52488, while the sum is 40.

The square root of 1266303991 is about 35585.1653220833. The cubic root of 1266303991 is about 1081.8805800827.

The spelling of 1266303991 in words is "one billion, two hundred sixty-six million, three hundred three thousand, nine hundred ninety-one".