19985728069 has 2 divisors, whose sum is σ = 19985728070. Its totient is φ = 19985728068.

The previous prime is 19985728043. The next prime is 19985728109. The reversal of 19985728069 is 96082758991.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 11352902500 + 8632825569 = 106550^2 + 92913^2 .

It is a cyclic number.

It is not a de Polignac number, because 19985728069 - 2³¹ = 17838244421 is a prime.

It is a super-2 number, since 2×19985728069² (a number of 21 digits) contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 19985728069.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (19985728019) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9992864034 + 9992864035.

It is an arithmetic number, because the mean of its divisors is an integer number (9992864035).

Almost surely, 2^19985728069 is an apocalyptic number.

It is an amenable number.

19985728069 is a deficient number, since it is larger than the sum of its proper divisors (1).

19985728069 is an equidigital number, since it uses as much as digits as its factorization.

19985728069 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 19595520, while the sum is 64.

The spelling of 19985728069 in words is "nineteen billion, nine hundred eighty-five million, seven hundred twenty-eight thousand, sixty-nine".