11111111111001 has 16 divisors (see below), whose sum is σ = 16505480337408. Its totient is φ = 6590729994000.

The previous prime is 11111111110997. The next prime is 11111111111017. The reversal of 11111111111001 is 10011111111111.

It is not a de Polignac number, because 11111111111001 - 2² = 11111111110997 is a prime.

It is not an unprimeable number, because it can be changed into a prime (11111111112001) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 3581916925 + ... + 3581920026.

It is an arithmetic number, because the mean of its divisors is an integer number (1031592521088).

Almost surely, 2^{11111111111001} is an apocalyptic number.

11111111111001 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

It is an amenable number.

11111111111001 is a deficient number, since it is larger than the sum of its proper divisors (5394369226407).

11111111111001 is a wasteful number, since it uses less digits than its factorization.

11111111111001 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7163837012.

The product of its (nonzero) digits is 1, while the sum is 12.

Adding to 11111111111001 its reverse (10011111111111), we get a palindrome (21122222222112).

It can be divided in two parts, 1111111111 and 1001, that multiplied together give a palindrome (1112222222111).

The spelling of 11111111111001 in words is "eleven trillion, one hundred eleven billion, one hundred eleven million, one hundred eleven thousand, one".