820406 has 4 divisors (see below), whose sum is σ = 1230612. Its totient is φ = 410202.

The previous prime is 820399. The next prime is 820409. The reversal of 820406 is 604028.

820406 is nontrivially palindromic in base 7.

It is a semiprime because it is the product of two primes.

It is a congruent number.

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

820406 is an untouchable number, because it is not equal to the sum of proper divisors of any number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 205100 + ... + 205103.

It is an arithmetic number, because the mean of its divisors is an integer number (307653).

2⁸²⁰⁴⁰⁶ is an apocalyptic number.

820406 is a deficient number, since it is larger than the sum of its proper divisors (410206).

820406 is a wasteful number, since it uses less digits than its factorization.

820406 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 410205.

The product of its (nonzero) digits is 384, while the sum is 20.

The square root of 820406 is about 905.7626620699. The cubic root of 820406 is about 93.6144613251.

The spelling of 820406 in words is "eight hundred twenty thousand, four hundred six".