1311218056491 has 64 divisors (see below), whose sum is σ = 2152660402176. Its totient is φ = 693414691200.

The previous prime is 1311218056469. The next prime is 1311218056513. The reversal of 1311218056491 is 1946508121131.

It is an interprime number because it is at equal distance from previous prime (1311218056469) and next prime (1311218056513).

It is not a de Polignac number, because 1311218056491 - 2⁵ = 1311218056459 is a prime.

It is not an unprimeable number, because it can be changed into a prime (1311218056441) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 99728580 + ... + 99741726.

It is an arithmetic number, because the mean of its divisors is an integer number (33635318784).

Almost surely, 2^{1311218056491} is an apocalyptic number.

1311218056491 is a deficient number, since it is larger than the sum of its proper divisors (841442345685).

1311218056491 is a wasteful number, since it uses less digits than its factorization.

1311218056491 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 19872.

The product of its (nonzero) digits is 51840, while the sum is 42.

The spelling of 1311218056491 in words is "one trillion, three hundred eleven billion, two hundred eighteen million, fifty-six thousand, four hundred ninety-one".