42109 has 4 divisors (see below), whose sum is σ = 44604. Its totient is φ = 39616.

The previous prime is 42101. The next prime is 42131. The reversal of 42109 is 90124.

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

It can be written as a sum of positive squares in 2 ways, for example, as 27225 + 14884 = 165^2 + 122^2 .

It is a cyclic number.

It is not a de Polignac number, because 42109 - 2³ = 42101 is a prime.

It is a Duffinian number.

42109 is a lucky number.

It is a plaindrome in base 14.

It is a junction number, because it is equal to n+sod(n) for n = 42092 and 42101.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (42101) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1222 + ... + 1255.

It is an arithmetic number, because the mean of its divisors is an integer number (11151).

2⁴²¹⁰⁹ is an apocalyptic number.

It is an amenable number.

42109 is a deficient number, since it is larger than the sum of its proper divisors (2495).

42109 is a wasteful number, since it uses less digits than its factorization.

42109 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2494.

The product of its (nonzero) digits is 72, while the sum is 16.

The square root of 42109 is about 205.2047757729. The cubic root of 42109 is about 34.7903108623.

It can be divided in two parts, 42 and 109, that added together give a palindrome (151).

The spelling of 42109 in words is "forty-two thousand, one hundred nine".