18971111981056 has 171 divisors, whose sum is σ = 38981971048737. Its totient is φ = 9232444293120.

The previous prime is 18971111981051. The next prime is 18971111981093. The reversal of 18971111981056 is 65018911117981.

The square root of 18971111981056 is 4355584.

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

It can be written as a sum of positive squares in only one way, i.e., 209046470656 + 18762065510400 = 457216^2 + 4331520^2 .

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (18971111981051) by changing a digit.

It is a polite number, since it can be written in 8 ways as a sum of consecutive naturals, for example, 104812773286 + ... + 104812773466.

Almost surely, 2^{18971111981056} is an apocalyptic number.

18971111981056 is a gapful number since it is divisible by the number (16) formed by its first and last digit.

18971111981056 is the 4355584-th square number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 18971111981056

18971111981056 is an abundant number, since it is smaller than the sum of its proper divisors (20010859067681).

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

18971111981056 is an frugal number, since it uses more digits than its factorization.

18971111981056 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 492 (or 230 counting only the distinct ones).

The product of its (nonzero) digits is 1088640, while the sum is 58.

The spelling of 18971111981056 in words is "eighteen trillion, nine hundred seventy-one billion, one hundred eleven million, nine hundred eighty-one thousand, fifty-six".