1311656163840 has 640 divisors, whose sum is σ = 5091102720000. Its totient is φ = 317449912320.

The previous prime is 1311656163817. The next prime is 1311656163859. The reversal of 1311656163840 is 483616561131.

1311656163840 is a `hidden beast` number, since 1 + 3 + 1 + 1 + 6 + 5 + 6 + 1 + 638 + 4 + 0 = 666.

It is a tau number, because it is divible by the number of its divisors (640).

It is a super-3 number, since 3×1311656163840³ (a number of 37 digits) contains 333 as substring.

It is a Harshad number since it is a multiple of its sum of digits (45).

It is an unprimeable number.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 656155161 + ... + 656157159.

It is an arithmetic number, because the mean of its divisors is an integer number (7954848000).

Almost surely, 2^{1311656163840} is an apocalyptic number.

1311656163840 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 1311656163840, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2545551360000).

1311656163840 is an abundant number, since it is smaller than the sum of its proper divisors (3779446556160).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

1311656163840 is a wasteful number, since it uses less digits than its factorization.

1311656163840 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2905 (or 2883 counting only the distinct ones).

The product of its (nonzero) digits is 311040, while the sum is 45.

The spelling of 1311656163840 in words is "one trillion, three hundred eleven billion, six hundred fifty-six million, one hundred sixty-three thousand, eight hundred forty".