1311789971556 has 27 divisors (see below), whose sum is σ = 3315930910201. Its totient is φ = 437261033184.

The previous prime is 1311789971477. The next prime is 1311789971567. The reversal of 1311789971556 is 6551799871131.

The square root of 1311789971556 is 1145334.

It is a perfect power (a square), and thus also a powerful number.

1311789971556 is a `hidden beast` number, since 1 + 3 + 1 + 1 + 7 + 8 + 9 + 9 + 71 + 556 = 666.

It can be written as a sum of positive squares in only one way, i.e., 14924531556 + 1296865440000 = 122166^2 + 1138800^2 .

It is a super-2 number, since 2×1311789971556² (a number of 25 digits) contains 22 as substring.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 1311789971493 and 1311789971502.

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 8 ways as a sum of consecutive naturals, for example, 6776560 + ... + 6967448.

Almost surely, 2^{1311789971556} is an apocalyptic number.

1311789971556 is the 1145334-th square number.

It is an amenable number.

1311789971556 is an abundant number, since it is smaller than the sum of its proper divisors (2004140938645).

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

1311789971556 is an frugal number, since it uses more digits than its factorization.

1311789971556 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 381788 (or 190894 counting only the distinct ones).

The product of its digits is 14288400, while the sum is 63.

The spelling of 1311789971556 in words is "one trillion, three hundred eleven billion, seven hundred eighty-nine million, nine hundred seventy-one thousand, five hundred fifty-six".