21131323 has 8 divisors (see below), whose sum is σ = 22585392. Its totient is φ = 19700736.

The previous prime is 21131317. The next prime is 21131333. The reversal of 21131323 is 32313112.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 21131323 - 2¹⁷ = 21000251 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21131297 and 21131306.

It is not an unprimeable number, because it can be changed into a prime (21131333) 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 7 ways as a sum of consecutive naturals, for example, 3990 + ... + 7627.

It is an arithmetic number, because the mean of its divisors is an integer number (2823174).

Almost surely, 2^21131323 is an apocalyptic number.

21131323 is a deficient number, since it is larger than the sum of its proper divisors (1454069).

21131323 is a wasteful number, since it uses less digits than its factorization.

21131323 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 11741.

The product of its digits is 108, while the sum is 16.

The square root of 21131323 is about 4596.8818779690. The cubic root of 21131323 is about 276.4663185584.

Adding to 21131323 its reverse (32313112), we get a palindrome (53444435).

The spelling of 21131323 in words is "twenty-one million, one hundred thirty-one thousand, three hundred twenty-three".