21244413 has 8 divisors (see below), whose sum is σ = 29816800. Its totient is φ = 13417488.

The previous prime is 21244369. The next prime is 21244417. The reversal of 21244413 is 31444212.

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

It is not a de Polignac number, because 21244413 - 2²⁰ = 20195837 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a self number, because there is not a number n which added to its sum of digits gives 21244413.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21244417) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 186298 + ... + 186411.

It is an arithmetic number, because the mean of its divisors is an integer number (3727100).

Almost surely, 2^21244413 is an apocalyptic number.

It is an amenable number.

21244413 is a deficient number, since it is larger than the sum of its proper divisors (8572387).

21244413 is a wasteful number, since it uses less digits than its factorization.

21244413 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 372731.

The product of its digits is 768, while the sum is 21.

The square root of 21244413 is about 4609.1661935756. The cubic root of 21244413 is about 276.9586361448.

Adding to 21244413 its reverse (31444212), we get a palindrome (52688625).

The spelling of 21244413 in words is "twenty-one million, two hundred forty-four thousand, four hundred thirteen".