1312781065 has 4 divisors (see below), whose sum is σ = 1575337284. Its totient is φ = 1050224848.

The previous prime is 1312781047. The next prime is 1312781081. The reversal of 1312781065 is 5601872131.

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 162486009 + 1150295056 = 12747^2 + 33916^2 .

It is a cyclic number.

It is not a de Polignac number, because 1312781065 - 2²⁵ = 1279226633 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 1312781065.

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 3 ways as a sum of consecutive naturals, for example, 131278102 + ... + 131278111.

It is an arithmetic number, because the mean of its divisors is an integer number (393834321).

Almost surely, 2^1312781065 is an apocalyptic number.

It is an amenable number.

1312781065 is a deficient number, since it is larger than the sum of its proper divisors (262556219).

1312781065 is an equidigital number, since it uses as much as digits as its factorization.

1312781065 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 262556218.

The product of its (nonzero) digits is 10080, while the sum is 34.

The square root of 1312781065 is about 36232.3207233542. The cubic root of 1312781065 is about 1094.9579336508.

The spelling of 1312781065 in words is "one billion, three hundred twelve million, seven hundred eighty-one thousand, sixty-five".