1028821 has 4 divisors (see below), whose sum is σ = 1035532. Its totient is φ = 1022112.

The previous prime is 1028809. The next prime is 1028837. The reversal of 1028821 is 1288201.

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 324900 + 703921 = 570^2 + 839^2 .

It is a cyclic number.

It is not a de Polignac number, because 1028821 - 2⁹ = 1028309 is a prime.

It is a Duffinian number.

1028821 is a lucky number.

It is a junction number, because it is equal to n+sod(n) for n = 1028792 and 1028801.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1028221) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 3120 + ... + 3433.

It is an arithmetic number, because the mean of its divisors is an integer number (258883).

2^1028821 is an apocalyptic number.

It is an amenable number.

1028821 is a deficient number, since it is larger than the sum of its proper divisors (6711).

1028821 is an equidigital number, since it uses as much as digits as its factorization.

1028821 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6710.

The product of its (nonzero) digits is 256, while the sum is 22.

The square root of 1028821 is about 1014.3081385851. The cubic root of 1028821 is about 100.9516155532.

It can be divided in two parts, 1028 and 821, that added together give a square (1849 = 43²).

The spelling of 1028821 in words is "one million, twenty-eight thousand, eight hundred twenty-one".