21324513 has 8 divisors (see below), whose sum is σ = 32494528. Its totient is φ = 12185424.

The previous prime is 21324509. The next prime is 21324529. The reversal of 21324513 is 31542312.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 21324513 - 2² = 21324509 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (21), and also a Moran number because the ratio is a prime number: 1015453 = 21324513 / (2 + 1 + 3 + 2 + 4 + 5 + 1 + 3).

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 21324513.

It is not an unprimeable number, because it can be changed into a prime (21324503) 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 7 ways as a sum of consecutive naturals, for example, 507706 + ... + 507747.

It is an arithmetic number, because the mean of its divisors is an integer number (4061816).

Almost surely, 2^21324513 is an apocalyptic number.

It is an amenable number.

21324513 is a deficient number, since it is larger than the sum of its proper divisors (11170015).

21324513 is a wasteful number, since it uses less digits than its factorization.

21324513 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1015463.

The product of its digits is 720, while the sum is 21.

The square root of 21324513 is about 4617.8472257103. The cubic root of 21324513 is about 277.3062814865.

Adding to 21324513 its reverse (31542312), we get a palindrome (52866825).

The spelling of 21324513 in words is "twenty-one million, three hundred twenty-four thousand, five hundred thirteen".