19998565511 has 2 divisors, whose sum is σ = 19998565512. Its totient is φ = 19998565510.

The previous prime is 19998565351. The next prime is 19998565513. The reversal of 19998565511 is 11556589991.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 19998565511 - 2²⁶ = 19931456647 is a prime.

It is a super-2 number, since 2×19998565511² (a number of 21 digits) contains 22 as substring.

Together with 19998565513, it forms a pair of twin primes.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (19998565513) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9999282755 + 9999282756.

It is an arithmetic number, because the mean of its divisors is an integer number (9999282756).

Almost surely, 2^19998565511 is an apocalyptic number.

19998565511 is a deficient number, since it is larger than the sum of its proper divisors (1).

19998565511 is an equidigital number, since it uses as much as digits as its factorization.

19998565511 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 4374000, while the sum is 59.

The spelling of 19998565511 in words is "nineteen billion, nine hundred ninety-eight million, five hundred sixty-five thousand, five hundred eleven".