• 111 can be written using four 4's:

See also 113.

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111 has 4 divisors (see below), whose sum is σ = 152. Its totient is φ = 72.

The previous prime is 109. The next prime is 113.

111 is nontrivially palindromic in base 6 and base 10.

111 is an esthetic number in base 13 and base 15, because in such bases its adjacent digits differ by 1.

It is a semiprime because it is the product of two primes.

It is an interprime number because it is at equal distance from previous prime (109) and next prime (113).

It is not a de Polignac number, because 111 - 2¹ = 109 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (3), and also a Moran number because the ratio is a prime number: 37 = 111 / (1 + 1 + 1).

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.

It is a D-number.

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

It is the 11-th Hogben number.

It is a Duffinian number.

111 is an undulating number in base 6.

111 is a modest number, since divided by 11 gives 1 as remainder.

111 is a lucky number.

It is an insolite number, because it is divisible by the sum (3) and by the product (1) of the squares of its digits.

111 is a nontrivial repdigit in base 10.

It is a plaindrome in base 4, base 8, base 9, base 10, base 14 and base 16.

It is a nialpdrome in base 5, base 10, base 11, base 12, base 13 and base 15.

It is a zygodrome in base 10.

It is a junction number, because it is equal to n+sod(n) for n = 96 and 105.

It is a congruent number.

It is a nontrivial repunit in base 10.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 16 + ... + 21.

It is an arithmetic number, because the mean of its divisors is an integer number (38).

It is the magic constant of a 6 × 6 magic square.

111 is the 6-th nonagonal number.

111 is a deficient number, since it is larger than the sum of its proper divisors (41).

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

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

The sum of its prime factors is 40.

The product of its digits is 1, while the sum is 3.

The square root of 111 is about 10.5356537529. The cubic root of 111 is about 4.8058955337.

The spelling of 111 in words is "one hundred eleven", and thus it is an aban number and an iban number.