21103321 has 2 divisors, whose sum is σ = 21103322. Its totient is φ = 21103320.

The previous prime is 21103309. The next prime is 21103337. The reversal of 21103321 is 12330112.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 17640000 + 3463321 = 4200^2 + 1861^2 .

It is a cyclic number.

It is not a de Polignac number, because 21103321 - 2⁷ = 21103193 is a prime.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (21103301) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10551660 + 10551661.

It is an arithmetic number, because the mean of its divisors is an integer number (10551661).

Almost surely, 2^21103321 is an apocalyptic number.

It is an amenable number.

21103321 is a deficient number, since it is larger than the sum of its proper divisors (1).

21103321 is an equidigital number, since it uses as much as digits as its factorization.

21103321 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 36, while the sum is 13.

The square root of 21103321 is about 4593.8351080551. The cubic root of 21103321 is about 276.3441455493.

Adding to 21103321 its reverse (12330112), we get a palindrome (33433433).

The spelling of 21103321 in words is "twenty-one million, one hundred three thousand, three hundred twenty-one".