21213323 has 4 divisors (see below), whose sum is σ = 21280560. Its totient is φ = 21146088.

The previous prime is 21213293. The next prime is 21213341. The reversal of 21213323 is 32331212.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 21213323 - 2¹⁴ = 21196939 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21213343) 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 in 3 ways as a sum of consecutive naturals, for example, 33143 + ... + 33776.

It is an arithmetic number, because the mean of its divisors is an integer number (5320140).

Almost surely, 2^21213323 is an apocalyptic number.

21213323 is a deficient number, since it is larger than the sum of its proper divisors (67237).

21213323 is an equidigital number, since it uses as much as digits as its factorization.

21213323 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 67236.

The product of its digits is 216, while the sum is 17.

The square root of 21213323 is about 4605.7923314018. The cubic root of 21213323 is about 276.8234657384.

Adding to 21213323 its reverse (32331212), we get a palindrome (53544535).

The spelling of 21213323 in words is "twenty-one million, two hundred thirteen thousand, three hundred twenty-three".