19825566613281 has 243 divisors, whose sum is σ = 34764396150393. Its totient is φ = 10874295843840.

The previous prime is 19825566613267. The next prime is 19825566613313. The reversal of 19825566613281 is 18231666552891.

The square root of 19825566613281 is 4452591.

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

It can be written as a sum of positive squares in 4 ways, for example, as 3622204497681 + 16203362115600 = 1903209^2 + 4025340^2 .

It is a de Polignac number, because none of the positive numbers 2^k-19825566613281 is a prime.

It is a super-2 number, since 2×19825566613281² (a number of 27 digits) contains 22 as substring.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (19825566613981) by changing a digit.

It is a polite number, since it can be written in 242 ways as a sum of consecutive naturals, for example, 185285669230 + ... + 185285669336.

Almost surely, 2^{19825566613281} is an apocalyptic number.

19825566613281 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

19825566613281 is the 4452591-st square number.

19825566613281 is the 2226296-th centered octagonal number.

It is an amenable number.

19825566613281 is a deficient number, since it is larger than the sum of its proper divisors (14938829537112).

19825566613281 is a wasteful number, since it uses less digits than its factorization.

19825566613281 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 462 (or 231 counting only the distinct ones).

The product of its digits is 37324800, while the sum is 63.

The spelling of 19825566613281 in words is "nineteen trillion, eight hundred twenty-five billion, five hundred sixty-six million, six hundred thirteen thousand, two hundred eighty-one".