21131303 has 4 divisors (see below), whose sum is σ = 21142968. Its totient is φ = 21119640.

The previous prime is 21131293. The next prime is 21131317. The reversal of 21131303 is 30313112.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length.

It is a cyclic number.

It is not a de Polignac number, because 21131303 - 2¹⁰ = 21130279 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 (21131333) 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, 2468 + ... + 6953.

It is an arithmetic number, because the mean of its divisors is an integer number (5285742).

Almost surely, 2^21131303 is an apocalyptic number.

21131303 is a deficient number, since it is larger than the sum of its proper divisors (11665).

21131303 is an equidigital number, since it uses as much as digits as its factorization.

21131303 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 11664.

The product of its (nonzero) digits is 54, while the sum is 14.

The square root of 21131303 is about 4596.8797025809. The cubic root of 21131303 is about 276.4662313367.

Adding to 21131303 its reverse (30313112), we get a palindrome (51444415).

The spelling of 21131303 in words is "twenty-one million, one hundred thirty-one thousand, three hundred three".