1266278889 has 4 divisors (see below), whose sum is σ = 1688371856. Its totient is φ = 844185924.

The previous prime is 1266278879. The next prime is 1266278929. The reversal of 1266278889 is 9888726621.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is not a de Polignac number, because 1266278889 - 2⁵ = 1266278857 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1266278879) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 211046479 + ... + 211046484.

It is an arithmetic number, because the mean of its divisors is an integer number (422092964).

Almost surely, 2^1266278889 is an apocalyptic number.

It is an amenable number.

1266278889 is a deficient number, since it is larger than the sum of its proper divisors (422092967).

1266278889 is an equidigital number, since it uses as much as digits as its factorization.

1266278889 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 422092966.

The product of its digits is 4644864, while the sum is 57.

The square root of 1266278889 is about 35584.8126171826. The cubic root of 1266278889 is about 1081.8734313132.

The spelling of 1266278889 in words is "one billion, two hundred sixty-six million, two hundred seventy-eight thousand, eight hundred eighty-nine".