401821 has 8 divisors (see below), whose sum is σ = 463680. Its totient is φ = 341088.

The previous prime is 401813. The next prime is 401827. The reversal of 401821 is 128104.

It is a happy number.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 401821 - 2³ = 401813 is a prime.

It is a super-2 number, since 2×401821² = 322920232082, which contains 22 as substring.

401821 is a lucky number.

It is a junction number, because it is equal to n+sod(n) for n = 401795 and 401804.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (401827) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 750 + ... + 1168.

It is an arithmetic number, because the mean of its divisors is an integer number (57960).

2⁴⁰¹⁸²¹ is an apocalyptic number.

It is an amenable number.

401821 is a deficient number, since it is larger than the sum of its proper divisors (61859).

401821 is a wasteful number, since it uses less digits than its factorization.

401821 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 563.

The product of its (nonzero) digits is 64, while the sum is 16.

The square root of 401821 is about 633.8935241821. The cubic root of 401821 is about 73.7922710844.

Adding to 401821 its reverse (128104), we get a palindrome (529925).

The spelling of 401821 in words is "four hundred one thousand, eight hundred twenty-one".