405421 has 4 divisors (see below), whose sum is σ = 423072. Its totient is φ = 387772.

The previous prime is 405413. The next prime is 405437. The reversal of 405421 is 124504.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 405421 - 2³ = 405413 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 405395 and 405404.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (405401) 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, 8791 + ... + 8836.

It is an arithmetic number, because the mean of its divisors is an integer number (105768).

2⁴⁰⁵⁴²¹ is an apocalyptic number.

It is an amenable number.

405421 is a deficient number, since it is larger than the sum of its proper divisors (17651).

405421 is a wasteful number, since it uses less digits than its factorization.

405421 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 17650.

The product of its (nonzero) digits is 160, while the sum is 16.

The square root of 405421 is about 636.7267859922. The cubic root of 405421 is about 74.0119897787.

Adding to 405421 its reverse (124504), we get a palindrome (529925).

The spelling of 405421 in words is "four hundred five thousand, four hundred twenty-one".