11111111 has 16 divisors (see below), whose sum is σ = 12499488. Its totient is φ = 9792000.

The previous prime is 11111101. The next prime is 11111117.

11111111 is nontrivially palindromic in base 10.

11111111 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-11111111 is a prime.

It is a nude number because it is divisible by every one of its digits and also a Zuckerman number because it is divisible by the product of its digits.

11111111 is a strobogrammatic number because it is the same when read upside-down.

It is a Duffinian number.

11111111 is a modest number, since divided by 11111 gives 111 as remainder.

11111111 is a nontrivial repdigit in base 10.

It is a plaindrome in base 10.

It is a nialpdrome in base 10.

It is a zygodrome in base 10.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (11111117) by changing a digit.

It is a nontrivial repunit in base 10.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 81035 + ... + 81171.

It is an arithmetic number, because the mean of its divisors is an integer number (781218).

Almost surely, 2^11111111 is an apocalyptic number.

11111111 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

11111111 is a deficient number, since it is larger than the sum of its proper divisors (1388377).

11111111 is a wasteful number, since it uses less digits than its factorization.

11111111 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 322.

The product of its digits is 1, while the sum is 8.

The square root of 11111111 is about 3333.3333166667. Note that the first 4 decimals coincide. The cubic root of 11111111 is about 223.1443159502.

It can be divided in two parts, 111111 and 11, that multiplied together give a palindrome (1222221).

The spelling of 11111111 in words is "eleven million, one hundred eleven thousand, one hundred eleven".