21345244 has 12 divisors (see below), whose sum is σ = 37387224. Its totient is φ = 10663184.

The previous prime is 21345241. The next prime is 21345253. The reversal of 21345244 is 44254312.

It is a happy number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21345241) 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, 6087 + ... + 8929.

It is an arithmetic number, because the mean of its divisors is an integer number (3115602).

Almost surely, 2^21345244 is an apocalyptic number.

It is an amenable number.

21345244 is a deficient number, since it is larger than the sum of its proper divisors (16041980).

21345244 is a wasteful number, since it uses less digits than its factorization.

21345244 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4724 (or 4722 counting only the distinct ones).

The product of its digits is 3840, while the sum is 25.

The square root of 21345244 is about 4620.0913410884. The cubic root of 21345244 is about 277.3961151063.

Adding to 21345244 its reverse (44254312), we get a palindrome (65599556).

The spelling of 21345244 in words is "twenty-one million, three hundred forty-five thousand, two hundred forty-four".