21323005 has 16 divisors (see below), whose sum is σ = 28024704. Its totient is φ = 15446080.

The previous prime is 21322999. The next prime is 21323011. The reversal of 21323005 is 50032312.

It is an interprime number because it is at equal distance from previous prime (21322999) and next prime (21323011).

It is not a de Polignac number, because 21323005 - 2⁹ = 21322493 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 21323005.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 16824 + ... + 18046.

It is an arithmetic number, because the mean of its divisors is an integer number (1751544).

Almost surely, 2^21323005 is an apocalyptic number.

It is an amenable number.

21323005 is a deficient number, since it is larger than the sum of its proper divisors (6701699).

21323005 is a wasteful number, since it uses less digits than its factorization.

21323005 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1556.

The product of its (nonzero) digits is 180, while the sum is 16.

The square root of 21323005 is about 4617.6839432772. The cubic root of 21323005 is about 277.2997446005.

Adding to 21323005 its reverse (50032312), we get a palindrome (71355317).

The spelling of 21323005 in words is "twenty-one million, three hundred twenty-three thousand, five".