405845 has 16 divisors (see below), whose sum is σ = 546048. Its totient is φ = 287040.

The previous prime is 405829. The next prime is 405857. The reversal of 405845 is 548504.

It is not a de Polignac number, because 405845 - 2⁴ = 405829 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 2507 + ... + 2663.

It is an arithmetic number, because the mean of its divisors is an integer number (34128).

2⁴⁰⁵⁸⁴⁵ is an apocalyptic number.

It is an amenable number.

405845 is a deficient number, since it is larger than the sum of its proper divisors (140203).

405845 is a wasteful number, since it uses less digits than its factorization.

405845 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 220.

The product of its (nonzero) digits is 3200, while the sum is 26.

The square root of 405845 is about 637.0596518380. The cubic root of 405845 is about 74.0377820213.

It can be divided in two parts, 405 and 845, that multiplied together give a square (342225 = 585²).

The spelling of 405845 in words is "four hundred five thousand, eight hundred forty-five".