800820001 has 4 divisors (see below), whose sum is σ = 811790212. Its totient is φ = 789849792.

The previous prime is 800819989. The next prime is 800820029. The reversal of 800820001 is 100028008.

It is a happy number.

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

It can be written as a sum of positive squares in 2 ways, for example, as 375429376 + 425390625 = 19376^2 + 20625^2 .

It is a cyclic number.

It is not a de Polignac number, because 800820001 - 2¹⁷ = 800688929 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (800820091) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 5484996 + ... + 5485141.

It is an arithmetic number, because the mean of its divisors is an integer number (202947553).

Almost surely, 2^800820001 is an apocalyptic number.

It is an amenable number.

800820001 is a deficient number, since it is larger than the sum of its proper divisors (10970211).

800820001 is a wasteful number, since it uses less digits than its factorization.

800820001 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10970210.

The product of its (nonzero) digits is 128, while the sum is 19.

The square root of 800820001 is about 28298.7632415270. The cubic root of 800820001 is about 928.6348340395.

Adding to 800820001 its reverse (100028008), we get a palindrome (900848009).

The spelling of 800820001 in words is "eight hundred million, eight hundred twenty thousand, one".