820001 has 8 divisors (see below), whose sum is σ = 1009344. Its totient is φ = 648720.

The previous prime is 819991. The next prime is 820037. The reversal of 820001 is 100028.

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 820001 - 2⁶ = 819937 is a prime.

It is an Ulam number.

It is a nialpdrome in base 16.

It is a zygodrome in base 12.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 820001.

It is not an unprimeable number, because it can be changed into a prime (820051) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 4415 + ... + 4596.

It is an arithmetic number, because the mean of its divisors is an integer number (126168).

2⁸²⁰⁰⁰¹ is an apocalyptic number.

It is an amenable number.

820001 is a deficient number, since it is larger than the sum of its proper divisors (189343).

820001 is a wasteful number, since it uses less digits than its factorization.

820001 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9031.

The product of its (nonzero) digits is 16, while the sum is 11.

The square root of 820001 is about 905.5390659712. The cubic root of 820001 is about 93.5990542798.

Adding to 820001 its reverse (100028), we get a palindrome (920029).

The spelling of 820001 in words is "eight hundred twenty thousand, one".