820404111 has 8 divisors (see below), whose sum is σ = 1094100480. Its totient is φ = 546821912.

The previous prime is 820404103. The next prime is 820404187. The reversal of 820404111 is 111404028.

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 820404111 - 2³ = 820404103 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (820408111) 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, 10065 + ... + 41738.

It is an arithmetic number, because the mean of its divisors is an integer number (136762560).

Almost surely, 2^820404111 is an apocalyptic number.

820404111 is a deficient number, since it is larger than the sum of its proper divisors (273696369).

820404111 is a wasteful number, since it uses less digits than its factorization.

820404111 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 57085.

The product of its (nonzero) digits is 256, while the sum is 21.

The square root of 820404111 is about 28642.6973415564. The cubic root of 820404111 is about 936.1438947541.

Adding to 820404111 its reverse (111404028), we get a palindrome (931808139).

The spelling of 820404111 in words is "eight hundred twenty million, four hundred four thousand, one hundred eleven".