19966893475489 has 81 divisors (see below), whose sum is σ = 22443424191513. Its totient is φ = 17759340115200.

The previous prime is 19966893475483. The next prime is 19966893475559. The reversal of 19966893475489 is 98457439866991.

The square root of 19966893475489 is 4468433.

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 1842358302225 + 18124535173264 = 1357335^2 + 4257292^2 .

It is not a de Polignac number, because 19966893475489 - 2¹⁵ = 19966893442721 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (19966893475483) by changing a digit.

It is a polite number, since it can be written in 80 ways as a sum of consecutive naturals, for example, 143646715582 + ... + 143646715720.

Almost surely, 2^{19966893475489} is an apocalyptic number.

19966893475489 is the 4468433-rd square number.

19966893475489 is the 2234217-th centered octagonal number.

It is an amenable number.

19966893475489 is a deficient number, since it is larger than the sum of its proper divisors (2476530716024).

19966893475489 is an frugal number, since it uses more digits than its factorization.

19966893475489 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 496 (or 248 counting only the distinct ones).

The product of its digits is 25395793920, while the sum is 88.

The spelling of 19966893475489 in words is "nineteen trillion, nine hundred sixty-six billion, eight hundred ninety-three million, four hundred seventy-five thousand, four hundred eighty-nine".