1266258665 has 16 divisors (see below), whose sum is σ = 1740372480. Its totient is φ = 866397120.

The previous prime is 1266258641. The next prime is 1266258671. The reversal of 1266258665 is 5668526621.

It is not a de Polignac number, because 1266258665 - 2²⁴ = 1249481449 is a prime.

It is a super-2 number, since 2×1266258665² = 3206822013375164450, which contains 22 as substring.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 23105 + ... + 55374.

It is an arithmetic number, because the mean of its divisors is an integer number (108773280).

Almost surely, 2^1266258665 is an apocalyptic number.

It is an amenable number.

1266258665 is a deficient number, since it is larger than the sum of its proper divisors (474113815).

1266258665 is an equidigital number, since it uses as much as digits as its factorization.

1266258665 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 78952.

The product of its digits is 1036800, while the sum is 47.

The square root of 1266258665 is about 35584.5284498755. The cubic root of 1266258665 is about 1081.8676716751.

The spelling of 1266258665 in words is "one billion, two hundred sixty-six million, two hundred fifty-eight thousand, six hundred sixty-five".