12105 has 12 divisors (see below), whose sum is σ = 21060. Its totient is φ = 6432.

The previous prime is 12101. The next prime is 12107. The reversal of 12105 is 50121.

It is a happy number.

It can be written as a sum of positive squares in 2 ways, for example, as 2304 + 9801 = 48^2 + 99^2 .

It is not a de Polignac number, because 12105 - 2² = 12101 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (9).

It is an alternating number because its digits alternate between odd and even.

It is not an unprimeable number, because it can be changed into a prime (12101) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 90 + ... + 179.

It is an arithmetic number, because the mean of its divisors is an integer number (1755).

12105 is a Friedman number, since it can be written as 110^2+5, using all its digits and the basic arithmetic operations.

2¹²¹⁰⁵ is an apocalyptic number.

12105 is a gapful number since it is divisible by the number (15) formed by its first and last digit.

12105 is the 90-th pentagonal number.

It is an amenable number.

12105 is a deficient number, since it is larger than the sum of its proper divisors (8955).

12105 is a wasteful number, since it uses less digits than its factorization.

12105 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 280 (or 277 counting only the distinct ones).

The product of its (nonzero) digits is 10, while the sum is 9.

The square root of 12105 is about 110.0227249254. The cubic root of 12105 is about 22.9608660294.

Adding to 12105 its reverse (50121), we get a palindrome (62226).

The spelling of 12105 in words is "twelve thousand, one hundred five".