426821 has 4 divisors (see below), whose sum is σ = 428352. Its totient is φ = 425292.

The previous prime is 426799. The next prime is 426841. The reversal of 426821 is 128624.

426821 is nontrivially palindromic in base 7.

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 426821 - 2⁶ = 426757 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (426841) 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, 215 + ... + 948.

It is an arithmetic number, because the mean of its divisors is an integer number (107088).

2⁴²⁶⁸²¹ is an apocalyptic number.

It is an amenable number.

426821 is a deficient number, since it is larger than the sum of its proper divisors (1531).

426821 is a wasteful number, since it uses less digits than its factorization.

426821 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1530.

The product of its digits is 768, while the sum is 23.

The square root of 426821 is about 653.3153909101. The cubic root of 426821 is about 75.2919582929.

The spelling of 426821 in words is "four hundred twenty-six thousand, eight hundred twenty-one".