13331821 has 2 divisors, whose sum is σ = 13331822. Its totient is φ = 13331820.

The previous prime is 13331819. The next prime is 13331831. The reversal of 13331821 is 12813331.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 13286025 + 45796 = 3645^2 + 214^2 .

It is a cyclic number.

It is not a de Polignac number, because 13331821 - 2¹ = 13331819 is a prime.

Together with 13331819, 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 = 13331792 and 13331801.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (13331831) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 6665910 + 6665911.

It is an arithmetic number, because the mean of its divisors is an integer number (6665911).

Almost surely, 2^13331821 is an apocalyptic number.

It is an amenable number.

13331821 is a deficient number, since it is larger than the sum of its proper divisors (1).

13331821 is an equidigital number, since it uses as much as digits as its factorization.

13331821 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 432, while the sum is 22.

The square root of 13331821 is about 3651.2766260583. The cubic root of 13331821 is about 237.1172546132.

The spelling of 13331821 in words is "thirteen million, three hundred thirty-one thousand, eight hundred twenty-one".