998111111 has 2 divisors, whose sum is σ = 998111112. Its totient is φ = 998111110.

The previous prime is 998111077. The next prime is 998111119. The reversal of 998111111 is 111111899.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-998111111 is a prime.

It is a Sophie Germain prime.

It is a Chen prime.

998111111 is a modest number, since divided by 11111 gives 9981 as remainder.

It is equal to p_50756450 and since 998111111 and 50756450 have the same sum of digits, it is a Honaker prime.

It is a nialpdrome in base 10.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (998111119) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 499055555 + 499055556.

It is an arithmetic number, because the mean of its divisors is an integer number (499055556).

Almost surely, 2^998111111 is an apocalyptic number.

998111111 is a deficient number, since it is larger than the sum of its proper divisors (1).

998111111 is an equidigital number, since it uses as much as digits as its factorization.

998111111 is an evil number, because the sum of its binary digits is even.

The product of its digits is 648, while the sum is 32.

The square root of 998111111 is about 31592.8965275424. The cubic root of 998111111 is about 999.3699734833.

The spelling of 998111111 in words is "nine hundred ninety-eight million, one hundred eleven thousand, one hundred eleven".