820401 has 16 divisors (see below), whose sum is σ = 1185600. Its totient is φ = 502848.

The previous prime is 820399. The next prime is 820409. The reversal of 820401 is 104028.

It is not a de Polignac number, because 820401 - 2¹ = 820399 is a prime.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (820409) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 1915 + ... + 2303.

It is an arithmetic number, because the mean of its divisors is an integer number (74100).

2⁸²⁰⁴⁰¹ is an apocalyptic number.

It is an amenable number.

820401 is a deficient number, since it is larger than the sum of its proper divisors (365199).

820401 is a wasteful number, since it uses less digits than its factorization.

820401 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 448.

The product of its (nonzero) digits is 64, while the sum is 15.

The square root of 820401 is about 905.7599019608. The cubic root of 820401 is about 93.6142711456.

Adding to 820401 its reverse (104028), we get a palindrome (924429).

It can be divided in two parts, 820 and 401, that added together give a palindrome (1221).

The spelling of 820401 in words is "eight hundred twenty thousand, four hundred one".