406405 has 4 divisors (see below), whose sum is σ = 487692. Its totient is φ = 325120.

The previous prime is 406403. The next prime is 406423. The reversal of 406405 is 504604.

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 294849 + 111556 = 543^2 + 334^2 .

It is not a de Polignac number, because 406405 - 2¹ = 406403 is a prime.

It is a Duffinian number.

406405 is a lucky number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (406403) 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, 40636 + ... + 40645.

It is an arithmetic number, because the mean of its divisors is an integer number (121923).

2⁴⁰⁶⁴⁰⁵ is an apocalyptic number.

It is an amenable number.

406405 is a deficient number, since it is larger than the sum of its proper divisors (81287).

406405 is an equidigital number, since it uses as much as digits as its factorization.

406405 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 81286.

The product of its (nonzero) digits is 480, while the sum is 19.

The square root of 406405 is about 637.4990196071. The cubic root of 406405 is about 74.0718197308.

The spelling of 406405 in words is "four hundred six thousand, four hundred five".