1331921 has 2 divisors, whose sum is σ = 1331922. Its totient is φ = 1331920.

The previous prime is 1331857. The next prime is 1331923. The reversal of 1331921 is 1291331.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 748225 + 583696 = 865^2 + 764^2 .

It is a cyclic number.

It is not a de Polignac number, because 1331921 - 2⁶ = 1331857 is a prime.

Together with 1331923, it forms a pair of twin primes.

It is a Chen prime.

It is a junction number, because it is equal to n+sod(n) for n = 1331893 and 1331902.

It is not a weakly prime, because it can be changed into another prime (1331923) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 665960 + 665961.

It is an arithmetic number, because the mean of its divisors is an integer number (665961).

2^1331921 is an apocalyptic number.

It is an amenable number.

1331921 is a deficient number, since it is larger than the sum of its proper divisors (1).

1331921 is an equidigital number, since it uses as much as digits as its factorization.

1331921 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 162, while the sum is 20.

The square root of 1331921 is about 1154.0888180725. The cubic root of 1331921 is about 110.0253660510.

The spelling of 1331921 in words is "one million, three hundred thirty-one thousand, nine hundred twenty-one".