405820 has 24 divisors (see below), whose sum is σ = 864864. Its totient is φ = 159936.

The previous prime is 405817. The next prime is 405827. The reversal of 405820 is 28504.

It is a happy number.

405820 is digitally balanced in base 3, because in such base it contains all the possibile digits an equal number of times.

It is a super-3 number, since 3×405820³ = 200503332052104000, which contains 333 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (405827) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1962 + ... + 2158.

It is an arithmetic number, because the mean of its divisors is an integer number (36036).

2⁴⁰⁵⁸²⁰ is an apocalyptic number.

It is an amenable number.

405820 is an abundant number, since it is smaller than the sum of its proper divisors (459044).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

405820 is a wasteful number, since it uses less digits than its factorization.

405820 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 309 (or 307 counting only the distinct ones).

The product of its (nonzero) digits is 320, while the sum is 19.

The square root of 405820 is about 637.0400301394. The cubic root of 405820 is about 74.0362617507.

It can be divided in two parts, 405 and 820, that added together give a triangular number (1225 = T₄₉).

The spelling of 405820 in words is "four hundred five thousand, eight hundred twenty".