1131821 has 2 divisors, whose sum is σ = 1131822. Its totient is φ = 1131820.

The previous prime is 1131799. The next prime is 1131827. The reversal of 1131821 is 1281311.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 662596 + 469225 = 814^2 + 685^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1131821 is a prime.

It is a Sophie Germain prime.

It is an Ulam number.

It is a Curzon number.

It is a self number, because there is not a number n which added to its sum of digits gives 1131821.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1131827) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 565910 + 565911.

It is an arithmetic number, because the mean of its divisors is an integer number (565911).

2^1131821 is an apocalyptic number.

It is an amenable number.

1131821 is a deficient number, since it is larger than the sum of its proper divisors (1).

1131821 is an equidigital number, since it uses as much as digits as its factorization.

1131821 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 48, while the sum is 17.

The square root of 1131821 is about 1063.8707628279. The cubic root of 1131821 is about 104.2139640856.

The spelling of 1131821 in words is "one million, one hundred thirty-one thousand, eight hundred twenty-one".