19985869 has 2 divisors, whose sum is σ = 19985870. Its totient is φ = 19985868.

The previous prime is 19985831. The next prime is 19985909. The reversal of 19985869 is 96858991.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 13032100 + 6953769 = 3610^2 + 2637^2 .

It is an emirp because it is prime and its reverse (96858991) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 19985869 - 2⁷ = 19985741 is a prime.

It is a super-2 number, since 2×19985869² = 798869919370322, which contains 22 as substring.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (19985969) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9992934 + 9992935.

It is an arithmetic number, because the mean of its divisors is an integer number (9992935).

Almost surely, 2^19985869 is an apocalyptic number.

It is an amenable number.

19985869 is a deficient number, since it is larger than the sum of its proper divisors (1).

19985869 is an equidigital number, since it uses as much as digits as its factorization.

19985869 is an evil number, because the sum of its binary digits is even.

The product of its digits is 1399680, while the sum is 55.

The square root of 19985869 is about 4470.5557820029. Note that the first 3 decimals coincide. The cubic root of 19985869 is about 271.3778175383.

It can be divided in two parts, 199 and 85869, that added together give a palindrome (86068).

The spelling of 19985869 in words is "nineteen million, nine hundred eighty-five thousand, eight hundred sixty-nine".