21833813 has 2 divisors, whose sum is σ = 21833814. Its totient is φ = 21833812.

The previous prime is 21833807. The next prime is 21833821. The reversal of 21833813 is 31833812.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 20448484 + 1385329 = 4522^2 + 1177^2 .

It is a cyclic number.

It is not a de Polignac number, because 21833813 - 2⁸ = 21833557 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21833863) 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, 10916906 + 10916907.

It is an arithmetic number, because the mean of its divisors is an integer number (10916907).

Almost surely, 2^21833813 is an apocalyptic number.

It is an amenable number.

21833813 is a deficient number, since it is larger than the sum of its proper divisors (1).

21833813 is an equidigital number, since it uses as much as digits as its factorization.

21833813 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 3456, while the sum is 29.

The square root of 21833813 is about 4672.6665834403. Note that the first 3 decimals coincide. The cubic root of 21833813 is about 279.4965997519.

Subtracting 21833813 from its reverse (31833812), we obtain a palindrome (9999999).

The spelling of 21833813 in words is "twenty-one million, eight hundred thirty-three thousand, eight hundred thirteen".