1311555065 has 4 divisors (see below), whose sum is σ = 1573866084. Its totient is φ = 1049244048.

The previous prime is 1311555019. The next prime is 1311555107. The reversal of 1311555065 is 5605551131.

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 549574249 + 761980816 = 23443^2 + 27604^2 .

It is a cyclic number.

It is not a de Polignac number, because 1311555065 - 2¹⁸ = 1311292921 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is an unprimeable number.

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 in 3 ways as a sum of consecutive naturals, for example, 131155502 + ... + 131155511.

It is an arithmetic number, because the mean of its divisors is an integer number (393466521).

Almost surely, 2^1311555065 is an apocalyptic number.

It is an amenable number.

1311555065 is a deficient number, since it is larger than the sum of its proper divisors (262311019).

1311555065 is an equidigital number, since it uses as much as digits as its factorization.

1311555065 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 262311018.

The product of its (nonzero) digits is 11250, while the sum is 32.

The square root of 1311555065 is about 36215.3981753618. The cubic root of 1311555065 is about 1094.6169688162.

The spelling of 1311555065 in words is "one billion, three hundred eleven million, five hundred fifty-five thousand, sixty-five".