21316323 has 12 divisors (see below), whose sum is σ = 33062280. Its totient is φ = 12180672.

The previous prime is 21316319. The next prime is 21316349. The reversal of 21316323 is 32361312.

It is not a de Polignac number, because 21316323 - 2² = 21316319 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (21).

It is a self number, because there is not a number n which added to its sum of digits gives 21316323.

It is not an unprimeable number, because it can be changed into a prime (21316223) 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 11 ways as a sum of consecutive naturals, for example, 72358 + ... + 72651.

It is an arithmetic number, because the mean of its divisors is an integer number (2755190).

Almost surely, 2^21316323 is an apocalyptic number.

21316323 is a deficient number, since it is larger than the sum of its proper divisors (11745957).

21316323 is a wasteful number, since it uses less digits than its factorization.

21316323 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 145026 (or 145019 counting only the distinct ones).

The product of its digits is 648, while the sum is 21.

The square root of 21316323 is about 4616.9603637025. The cubic root of 21316323 is about 277.2707757243.

Adding to 21316323 its reverse (32361312), we get a palindrome (53677635).

The spelling of 21316323 in words is "twenty-one million, three hundred sixteen thousand, three hundred twenty-three".