403821 has 12 divisors (see below), whose sum is σ = 636480. Its totient is φ = 244680.

The previous prime is 403817. The next prime is 403829. The reversal of 403821 is 128304.

It is a happy number.

It is not a de Polignac number, because 403821 - 2² = 403817 is a prime.

403821 is a lucky number.

It is a junction number, because it is equal to n+sod(n) for n = 403794 and 403803.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (403829) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 1941 + ... + 2138.

It is an arithmetic number, because the mean of its divisors is an integer number (53040).

2⁴⁰³⁸²¹ is an apocalyptic number.

It is an amenable number.

403821 is a deficient number, since it is larger than the sum of its proper divisors (232659).

403821 is a wasteful number, since it uses less digits than its factorization.

403821 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4096 (or 4093 counting only the distinct ones).

The product of its (nonzero) digits is 192, while the sum is 18.

The square root of 403821 is about 635.4691180537. The cubic root of 403821 is about 73.9144982764.

The spelling of 403821 in words is "four hundred three thousand, eight hundred twenty-one".