19986371654544 has 135 divisors (see below), whose sum is σ = 56498023577073. Its totient is φ = 6595619060736.

The previous prime is 19986371654521. The next prime is 19986371654551. The reversal of 19986371654544 is 44545617368991.

The square root of 19986371654544 is 4470612.

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

19986371654544 is a `hidden beast` number, since 1 + 9 + 9 + 8 + 6 + 3 + 7 + 165 + 454 + 4 = 666.

It can be written as a sum of positive squares in only one way, i.e., 99338432400 + 19887033222144 = 315180^2 + 4459488^2 .

It is a Harshad number since it is a multiple of its sum of digits (72).

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 26 ways as a sum of consecutive naturals, for example, 5525674624 + ... + 5525678240.

Almost surely, 2^{19986371654544} is an apocalyptic number.

19986371654544 is the 4470612-nd square number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 19986371654544

19986371654544 is an abundant number, since it is smaller than the sum of its proper divisors (36511651922529).

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

19986371654544 is an frugal number, since it uses more digits than its factorization.

19986371654544 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7454 (or 3725 counting only the distinct ones).

The product of its digits is 783820800, while the sum is 72.

The spelling of 19986371654544 in words is "nineteen trillion, nine hundred eighty-six billion, three hundred seventy-one million, six hundred fifty-four thousand, five hundred forty-four".