198511111 has 2 divisors, whose sum is σ = 198511112. Its totient is φ = 198511110.

The previous prime is 198511109. The next prime is 198511139. The reversal of 198511111 is 111115891.

It is a happy number.

It is an a-pointer prime, because the next prime (198511139) can be obtained adding 198511111 to its sum of digits (28).

It is a weak prime.

It is an emirp because it is prime and its reverse (111115891) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 198511111 - 2¹ = 198511109 is a prime.

It is a super-2 number, since 2×198511111² = 78813322380908642, which contains 22 as substring.

Together with 198511109, it forms a pair of twin primes.

198511111 is a modest number, since divided by 11111 gives 1985 as remainder.

It is a self number, because there is not a number n which added to its sum of digits gives 198511111.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (198511211) 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, 99255555 + 99255556.

It is an arithmetic number, because the mean of its divisors is an integer number (99255556).

Almost surely, 2^198511111 is an apocalyptic number.

198511111 is a deficient number, since it is larger than the sum of its proper divisors (1).

198511111 is an equidigital number, since it uses as much as digits as its factorization.

198511111 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 360, while the sum is 28.

The square root of 198511111 is about 14089.3971127227. The cubic root of 198511111 is about 583.3487523181.

The spelling of 198511111 in words is "one hundred ninety-eight million, five hundred eleven thousand, one hundred eleven".