1264266665 has 4 divisors (see below), whose sum is σ = 1517120004. Its totient is φ = 1011413328.

The previous prime is 1264266649. The next prime is 1264266667. The reversal of 1264266665 is 5666624621.

It is a happy number.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 990297961 + 273968704 = 31469^2 + 16552^2 .

It is a cyclic number.

It is not a de Polignac number, because 1264266665 - 2⁴ = 1264266649 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1264266667) by changing a digit.

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 3 ways as a sum of consecutive naturals, for example, 126426662 + ... + 126426671.

It is an arithmetic number, because the mean of its divisors is an integer number (379280001).

Almost surely, 2^1264266665 is an apocalyptic number.

It is an amenable number.

1264266665 is a deficient number, since it is larger than the sum of its proper divisors (252853339).

1264266665 is an equidigital number, since it uses as much as digits as its factorization.

1264266665 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 252853338.

The product of its digits is 622080, while the sum is 44.

The square root of 1264266665 is about 35556.5277410492. The cubic root of 1264266665 is about 1081.3000647739.

The spelling of 1264266665 in words is "one billion, two hundred sixty-four million, two hundred sixty-six thousand, six hundred sixty-five".