21324243 has 16 divisors (see below), whose sum is σ = 29836800. Its totient is φ = 13521024.

The previous prime is 21324227. The next prime is 21324253. The reversal of 21324243 is 34242312.

It is not a de Polignac number, because 21324243 - 2⁴ = 21324227 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21324203) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 12955 + ... + 14507.

It is an arithmetic number, because the mean of its divisors is an integer number (1864800).

Almost surely, 2^21324243 is an apocalyptic number.

21324243 is a gapful number since it is divisible by the number (23) formed by its first and last digit.

21324243 is a deficient number, since it is larger than the sum of its proper divisors (8512557).

21324243 is a wasteful number, since it uses less digits than its factorization.

21324243 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1778.

The product of its digits is 1152, while the sum is 21.

The square root of 21324243 is about 4617.8179912162. The cubic root of 21324243 is about 277.3051111118.

Adding to 21324243 its reverse (34242312), we get a palindrome (55566555).

The spelling of 21324243 in words is "twenty-one million, three hundred twenty-four thousand, two hundred forty-three".