19009957521681 has 567 divisors, whose sum is σ = 37452813774411. Its totient is φ = 9613576482048.

The previous prime is 19009957521679. The next prime is 19009957521733. The reversal of 19009957521681 is 18612575990091.

The square root of 19009957521681 is 4360041.

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

19009957521681 is a `hidden beast` number, since 19 + 0 + 0 + 9 + 95 + 7 + 521 + 6 + 8 + 1 = 666.

It can be written as a sum of positive squares in only one way, i.e., 14800139939025 + 4209817582656 = 3847095^2 + 2051784^2 .

It is a tau number, because it is divible by the number of its divisors (567).

It is not a de Polignac number, because 19009957521681 - 2¹ = 19009957521679 is a prime.

It is a super-2 number, since 2×19009957521681² (a number of 27 digits) contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (63).

It is not an unprimeable number, because it can be changed into a prime (19009957541681) by changing a digit.

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 566 ways as a sum of consecutive naturals, for example, 322202669830 + ... + 322202669888.

Almost surely, 2^{19009957521681} is an apocalyptic number.

19009957521681 is the 4360041-st square number.

19009957521681 is the 2180021-st centered octagonal number.

It is an amenable number.

19009957521681 is a deficient number, since it is larger than the sum of its proper divisors (18442856252730).

19009957521681 is an frugal number, since it uses more digits than its factorization.

19009957521681 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 230 (or 109 counting only the distinct ones).

The product of its (nonzero) digits is 12247200, while the sum is 63.

The spelling of 19009957521681 in words is "nineteen trillion, nine billion, nine hundred fifty-seven million, five hundred twenty-one thousand, six hundred eighty-one".