1266123787 has 2 divisors, whose sum is σ = 1266123788. Its totient is φ = 1266123786.

The previous prime is 1266123763. The next prime is 1266123821. The reversal of 1266123787 is 7873216621.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 1266123787 - 2⁷ = 1266123659 is a prime.

It is not a weakly prime, because it can be changed into another prime (1266123487) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 633061893 + 633061894.

It is an arithmetic number, because the mean of its divisors is an integer number (633061894).

Almost surely, 2^1266123787 is an apocalyptic number.

1266123787 is a deficient number, since it is larger than the sum of its proper divisors (1).

1266123787 is an equidigital number, since it uses as much as digits as its factorization.

1266123787 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 169344, while the sum is 43.

The square root of 1266123787 is about 35582.6332218401. The cubic root of 1266123787 is about 1081.8292578993.

The spelling of 1266123787 in words is "one billion, two hundred sixty-six million, one hundred twenty-three thousand, seven hundred eighty-seven".