421823 has 4 divisors (see below), whose sum is σ = 425040. Its totient is φ = 418608.

The previous prime is 421807. The next prime is 421831. The reversal of 421823 is 328124.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 421823 - 2⁴ = 421807 is a prime.

It is a Duffinian number.

It is a plaindrome in base 13.

It is a junction number, because it is equal to n+sod(n) for n = 421795 and 421804.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (421123) 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, 1403 + ... + 1676.

It is an arithmetic number, because the mean of its divisors is an integer number (106260).

2⁴²¹⁸²³ is an apocalyptic number.

421823 is a deficient number, since it is larger than the sum of its proper divisors (3217).

421823 is a wasteful number, since it uses less digits than its factorization.

421823 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3216.

The product of its digits is 384, while the sum is 20.

The square root of 421823 is about 649.4790219861. The cubic root of 421823 is about 74.9969183919.

Adding to 421823 its reverse (328124), we get a palindrome (749947).

The spelling of 421823 in words is "four hundred twenty-one thousand, eight hundred twenty-three".