1111111001001 has 6 divisors (see below), whose sum is σ = 1604938112570. Its totient is φ = 740740667328.

The previous prime is 1111111000957. The next prime is 1111111001027. The reversal of 1111111001001 is 1001001111111.

It can be written as a sum of positive squares in only one way, i.e., 1032867722601 + 78243278400 = 1016301^2 + 279720^2 .

It is not a de Polignac number, because 1111111001001 - 2¹⁴ = 1111110984617 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (9), and also a Moran number because the ratio is a prime number: 123456777889 = 1111111001001 / (1 + 1 + 1 + 1 + 1 + 1 + 1 + 0 + 0 + 1 + 0 + 0 + 1).

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1111111001071) 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 in 5 ways as a sum of consecutive naturals, for example, 61728388936 + ... + 61728388953.

Almost surely, 2^{1111111001001} is an apocalyptic number.

It is an amenable number.

1111111001001 is a deficient number, since it is larger than the sum of its proper divisors (493827111569).

1111111001001 is a wasteful number, since it uses less digits than its factorization.

1111111001001 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 123456777895 (or 123456777892 counting only the distinct ones).

The product of its (nonzero) digits is 1, while the sum is 9.

Adding to 1111111001001 its reverse (1001001111111), we get a palindrome (2112112112112).

It can be divided in two parts, 111111 and 1001001, that multiplied together give a palindrome (111222222111).

The spelling of 1111111001001 in words is "one trillion, one hundred eleven billion, one hundred eleven million, one thousand, one".