111001001 has 2 divisors, whose sum is σ = 111001002. Its totient is φ = 111001000.

The previous prime is 111000961. The next prime is 111001003. The reversal of 111001001 is 100100111.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 78499600 + 32501401 = 8860^2 + 5701^2 .

It is an emirp because it is prime and its reverse (100100111) is a distict prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-111001001 is a prime.

Together with 111001003, it forms a pair of twin primes.

It is a Chen prime.

111001001 is a modest number, since divided by 1001 gives 111 as remainder.

It is not a weakly prime, because it can be changed into another prime (111001003) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 55500500 + 55500501.

It is an arithmetic number, because the mean of its divisors is an integer number (55500501).

Almost surely, 2^111001001 is an apocalyptic number.

It is an amenable number.

111001001 is a deficient number, since it is larger than the sum of its proper divisors (1).

111001001 is an equidigital number, since it uses as much as digits as its factorization.

111001001 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 1, while the sum is 5.

The square root of 111001001 is about 10535.7012581033. The cubic root of 111001001 is about 480.5909980213.

Adding to 111001001 its reverse (100100111), we get a palindrome (211101112).

It can be divided in two parts, 11 and 1001001, that multiplied together give a palindrome (11011011).

The spelling of 111001001 in words is "one hundred eleven million, one thousand, one".