1311255444561 has 4 divisors (see below), whose sum is σ = 1748340592752. Its totient is φ = 874170296372.

The previous prime is 1311255444547. The next prime is 1311255444589. The reversal of 1311255444561 is 1654445521131.

It is a happy number.

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 a cyclic number.

It is not a de Polignac number, because 1311255444561 - 2²⁹ = 1310718573649 is a prime.

It is not an unprimeable number, because it can be changed into a prime (1311255444361) by changing a digit.

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, 218542574091 + ... + 218542574096.

It is an arithmetic number, because the mean of its divisors is an integer number (437085148188).

Almost surely, 2^{1311255444561} is an apocalyptic number.

It is an amenable number.

1311255444561 is a deficient number, since it is larger than the sum of its proper divisors (437085148191).

1311255444561 is an equidigital number, since it uses as much as digits as its factorization.

1311255444561 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 437085148190.

The product of its digits is 288000, while the sum is 42.

The spelling of 1311255444561 in words is "one trillion, three hundred eleven billion, two hundred fifty-five million, four hundred forty-four thousand, five hundred sixty-one".