19998006881 has 2 divisors, whose sum is σ = 19998006882. Its totient is φ = 19998006880.

The previous prime is 19998006859. The next prime is 19998006883. The reversal of 19998006881 is 18860089991.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 16750830625 + 3247176256 = 129425^2 + 56984^2 .

It is an emirp because it is prime and its reverse (18860089991) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 19998006881 - 2⁶ = 19998006817 is a prime.

It is a super-2 number, since 2×19998006881² (a number of 21 digits) contains 22 as substring.

Together with 19998006883, it forms a pair of twin primes.

It is a Chen prime.

It is a self number, because there is not a number n which added to its sum of digits gives 19998006881.

It is not a weakly prime, because it can be changed into another prime (19998006883) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9999003440 + 9999003441.

It is an arithmetic number, because the mean of its divisors is an integer number (9999003441).

Almost surely, 2^19998006881 is an apocalyptic number.

It is an amenable number.

19998006881 is a deficient number, since it is larger than the sum of its proper divisors (1).

19998006881 is an equidigital number, since it uses as much as digits as its factorization.

19998006881 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 2239488, while the sum is 59.

The spelling of 19998006881 in words is "nineteen billion, nine hundred ninety-eight million, six thousand, eight hundred eighty-one".