1000821 has 8 divisors (see below), whose sum is σ = 1339200.
Its totient is φ = 664832.
The previous prime is 1000793. The next prime is 1000829. The reversal of 1000821 is 1280001.
Adding to 1000821 its reverse (1280001), we get a palindrome (2280822).
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 1000821 - 214 = 984437 is a prime.
It is a junction number, because it is equal to n+sod(n) for n = 1000797 and 1000806.
It is a congruent number.
It is not an unprimeable number, because it can be changed into a prime (1000829) 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, 976 + ... + 1718.
It is an arithmetic number, because the mean of its divisors is an integer number (167400).
21000821 is an apocalyptic number.
It is an amenable number.
1000821 is a deficient number, since it is larger than the sum of its proper divisors (338379).
1000821 is an equidigital number, since it uses as much as digits as its factorization.
1000821 is an evil number, because the sum of its binary digits is even.
The sum of its prime factors is 1195.
The product of its (nonzero) digits is 16, while the sum is 12.
The square root of 1000821 is about 1000.4104157794.
The cubic root of 1000821 is about 100.0273591807.
The spelling of 1000821 in words is "one million, eight hundred twenty-one", and thus it is an aban number.