21144313 has 4 divisors (see below), whose sum is σ = 21594240. Its totient is φ = 20694388.

The previous prime is 21144307. The next prime is 21144323. The reversal of 21144313 is 31344112.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21144313 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21144323) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 224893 + ... + 224986.

It is an arithmetic number, because the mean of its divisors is an integer number (5398560).

Almost surely, 2^21144313 is an apocalyptic number.

It is an amenable number.

21144313 is a deficient number, since it is larger than the sum of its proper divisors (449927).

21144313 is an equidigital number, since it uses as much as digits as its factorization.

21144313 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 449926.

The product of its digits is 288, while the sum is 19.

The square root of 21144313 is about 4598.2945751659. The cubic root of 21144313 is about 276.5229574137.

Adding to 21144313 its reverse (31344112), we get a palindrome (52488425).

The spelling of 21144313 in words is "twenty-one million, one hundred forty-four thousand, three hundred thirteen".