21324245 has 4 divisors (see below), whose sum is σ = 25589100. Its totient is φ = 17059392.

The previous prime is 21324227. The next prime is 21324253. The reversal of 21324245 is 54242312.

It is a happy number.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 5276209 + 16048036 = 2297^2 + 4006^2 .

It is a cyclic number.

It is not a de Polignac number, because 21324245 - 2⁶ = 21324181 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 21324245.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2132420 + ... + 2132429.

It is an arithmetic number, because the mean of its divisors is an integer number (6397275).

Almost surely, 2^21324245 is an apocalyptic number.

It is an amenable number.

21324245 is a deficient number, since it is larger than the sum of its proper divisors (4264855).

21324245 is an equidigital number, since it uses as much as digits as its factorization.

21324245 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4264854.

The product of its digits is 1920, while the sum is 23.

The square root of 21324245 is about 4617.8182077687. The cubic root of 21324245 is about 277.3051197813.

Adding to 21324245 its reverse (54242312), we get a palindrome (75566557).

The spelling of 21324245 in words is "twenty-one million, three hundred twenty-four thousand, two hundred forty-five".