42405 has 16 divisors (see below), whose sum is σ = 74304. Its totient is φ = 20480.

The previous prime is 42403. The next prime is 42407. The reversal of 42405 is 50424.

42405 is nontrivially palindromic in base 2 and base 9.

42405 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is an interprime number because it is at equal distance from previous prime (42403) and next prime (42407).

It is not a de Polignac number, because 42405 - 2¹ = 42403 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (15).

It is an Ulam number.

42405 is an undulating number in base 16.

It is a Curzon number.

42405 is a lucky number.

It is a nialpdrome in base 15.

It is a zygodrome in base 4.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (42403) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 37 + ... + 293.

It is an arithmetic number, because the mean of its divisors is an integer number (4644).

2⁴²⁴⁰⁵ is an apocalyptic number.

It is an amenable number.

42405 is a deficient number, since it is larger than the sum of its proper divisors (31899).

42405 is a wasteful number, since it uses less digits than its factorization.

42405 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 276.

The product of its (nonzero) digits is 160, while the sum is 15.

The square root of 42405 is about 205.9247435351. The cubic root of 42405 is about 34.8716386581.

Adding to 42405 its reverse (50424), we get a palindrome (92829).

The spelling of 42405 in words is "forty-two thousand, four hundred five".