19989765894673 has 2 divisors, whose sum is σ = 19989765894674. Its totient is φ = 19989765894672.

The previous prime is 19989765894649. The next prime is 19989765894727. The reversal of 19989765894673 is 37649856798991.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 19932447788929 + 57318105744 = 4464577^2 + 239412^2 .

It is a cyclic number.

It is not a de Polignac number, because 19989765894673 - 2²⁵ = 19989732340241 is a prime.

It is a super-3 number, since 3×19989765894673³ (a number of 41 digits) contains 333 as substring.

It is not a weakly prime, because it can be changed into another prime (19989765294673) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9994882947336 + 9994882947337.

It is an arithmetic number, because the mean of its divisors is an integer number (9994882947337).

Almost surely, 2^{19989765894673} is an apocalyptic number.

It is an amenable number.

19989765894673 is a deficient number, since it is larger than the sum of its proper divisors (1).

19989765894673 is an equidigital number, since it uses as much as digits as its factorization.

19989765894673 is an evil number, because the sum of its binary digits is even.

The product of its digits is 44442639360, while the sum is 91.

The spelling of 19989765894673 in words is "nineteen trillion, nine hundred eighty-nine billion, seven hundred sixty-five million, eight hundred ninety-four thousand, six hundred seventy-three".