19891635680016 has 225 divisors, whose sum is σ = 57931751722383. Its totient is φ = 6589388309760.

The previous prime is 19891635679997. The next prime is 19891635680071. The reversal of 19891635680016 is 61008653619891.

The square root of 19891635680016 is 4460004.

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

19891635680016 is a `hidden beast` number, since 1 + 9 + 8 + 9 + 1 + 63 + 568 + 0 + 0 + 1 + 6 = 666.

It can be written as a sum of positive squares in 4 ways, for example, as 3260899193616 + 16630736486400 = 1805796^2 + 4078080^2 .

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 44 ways as a sum of consecutive naturals, for example, 36768272706 + ... + 36768273246.

Almost surely, 2^{19891635680016} is an apocalyptic number.

19891635680016 is a gapful number since it is divisible by the number (16) formed by its first and last digit.

19891635680016 is the 4460004-th square number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 19891635680016

19891635680016 is an abundant number, since it is smaller than the sum of its proper divisors (38040116042367).

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

19891635680016 is an frugal number, since it uses more digits than its factorization.

19891635680016 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1560 (or 775 counting only the distinct ones).

The product of its (nonzero) digits is 16796160, while the sum is 63.

The spelling of 19891635680016 in words is "nineteen trillion, eight hundred ninety-one billion, six hundred thirty-five million, six hundred eighty thousand, sixteen".