21606323 has 8 divisors (see below), whose sum is σ = 22171968. Its totient is φ = 21045184.

The previous prime is 21606313. The next prime is 21606359. The reversal of 21606323 is 32360612.

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 21606323 - 2⁶ = 21606259 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21606313) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 9965 + ... + 11937.

It is an arithmetic number, because the mean of its divisors is an integer number (2771496).

Almost surely, 2^21606323 is an apocalyptic number.

21606323 is a deficient number, since it is larger than the sum of its proper divisors (565645).

21606323 is a wasteful number, since it uses less digits than its factorization.

21606323 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2253.

The product of its (nonzero) digits is 1296, while the sum is 23.

The square root of 21606323 is about 4648.2602121654. The cubic root of 21606323 is about 278.5225021491.

Adding to 21606323 its reverse (32360612), we get a palindrome (53966935).

The spelling of 21606323 in words is "twenty-one million, six hundred six thousand, three hundred twenty-three".