21033313 has 4 divisors (see below), whose sum is σ = 24038080. Its totient is φ = 18028548.

The previous prime is 21033289. The next prime is 21033317. The reversal of 21033313 is 31333012.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 21033313 - 2¹⁷ = 20902241 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21033317) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1502373 + ... + 1502386.

It is an arithmetic number, because the mean of its divisors is an integer number (6009520).

Almost surely, 2^21033313 is an apocalyptic number.

It is an amenable number.

21033313 is a deficient number, since it is larger than the sum of its proper divisors (3004767).

21033313 is an equidigital number, since it uses as much as digits as its factorization.

21033313 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3004766.

The product of its (nonzero) digits is 162, while the sum is 16.

The square root of 21033313 is about 4586.2090009070. The cubic root of 21033313 is about 276.0382263444.

Adding to 21033313 its reverse (31333012), we get a palindrome (52366325).

The spelling of 21033313 in words is "twenty-one million, thirty-three thousand, three hundred thirteen".