425821 has 4 divisors (see below), whose sum is σ = 464544. Its totient is φ = 387100.

The previous prime is 425819. The next prime is 425837. The reversal of 425821 is 128524.

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 425821 - 2¹ = 425819 is a prime.

It is a Smith number, since the sum of its digits (22) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 425792 and 425801.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (425801) 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, 19345 + ... + 19366.

It is an arithmetic number, because the mean of its divisors is an integer number (116136).

2⁴²⁵⁸²¹ is an apocalyptic number.

It is an amenable number.

425821 is a deficient number, since it is larger than the sum of its proper divisors (38723).

425821 is a wasteful number, since it uses less digits than its factorization.

425821 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 38722.

The product of its digits is 640, while the sum is 22.

The square root of 425821 is about 652.5496149719. The cubic root of 425821 is about 75.2331117386.

The spelling of 425821 in words is "four hundred twenty-five thousand, eight hundred twenty-one".