1128821 has 2 divisors, whose sum is σ = 1128822. Its totient is φ = 1128820.

The previous prime is 1128811. The next prime is 1128823. The reversal of 1128821 is 1288211.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1030225 + 98596 = 1015^2 + 314^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1128821 is a prime.

It is a Sophie Germain prime.

Together with 1128823, it forms a pair of twin primes.

It is a Chen prime.

It is a Curzon number.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1128823) 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 as a sum of consecutive naturals, namely, 564410 + 564411.

It is an arithmetic number, because the mean of its divisors is an integer number (564411).

2^1128821 is an apocalyptic number.

It is an amenable number.

1128821 is a deficient number, since it is larger than the sum of its proper divisors (1).

1128821 is an equidigital number, since it uses as much as digits as its factorization.

1128821 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 256, while the sum is 23.

The square root of 1128821 is about 1062.4598815955. The cubic root of 1128821 is about 104.1218062476.

The spelling of 1128821 in words is "one million, one hundred twenty-eight thousand, eight hundred twenty-one".