803821 has 4 divisors (see below), whose sum is σ = 808444. Its totient is φ = 799200.

The previous prime is 803819. The next prime is 803849. The reversal of 803821 is 128308.

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 114921 + 688900 = 339^2 + 830^2 .

It is a cyclic number.

It is not a de Polignac number, because 803821 - 2¹ = 803819 is a prime.

It is a super-2 number, since 2×803821² = 1292256400082, which contains 22 as substring.

It is a Duffinian number.

803821 is a lucky number.

It is a junction number, because it is equal to n+sod(n) for n = 803792 and 803801.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (803921) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2040 + ... + 2401.

It is an arithmetic number, because the mean of its divisors is an integer number (202111).

2⁸⁰³⁸²¹ is an apocalyptic number.

It is an amenable number.

803821 is a deficient number, since it is larger than the sum of its proper divisors (4623).

803821 is a wasteful number, since it uses less digits than its factorization.

803821 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4622.

The product of its (nonzero) digits is 384, while the sum is 22.

The square root of 803821 is about 896.5606504861. The cubic root of 803821 is about 92.9793379157.

The spelling of 803821 in words is "eight hundred three thousand, eight hundred twenty-one".