21021303 has 4 divisors (see below), whose sum is σ = 28028408. Its totient is φ = 14014200.

The previous prime is 21021293. The next prime is 21021323. The reversal of 21021303 is 30312012.

It is a happy number.

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

It is not a de Polignac number, because 21021303 - 2⁸ = 21021047 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21021323) 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, 3503548 + ... + 3503553.

It is an arithmetic number, because the mean of its divisors is an integer number (7007102).

Almost surely, 2^21021303 is an apocalyptic number.

21021303 is a deficient number, since it is larger than the sum of its proper divisors (7007105).

21021303 is an equidigital number, since it uses as much as digits as its factorization.

21021303 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7007104.

The product of its (nonzero) digits is 36, while the sum is 12.

The square root of 21021303 is about 4584.8994536413. The cubic root of 21021303 is about 275.9856771605.

Adding to 21021303 its reverse (30312012), we get a palindrome (51333315).

The spelling of 21021303 in words is "twenty-one million, twenty-one thousand, three hundred three".