21444521 has 8 divisors (see below), whose sum is σ = 25798080. Its totient is φ = 17413488.

The previous prime is 21444499. The next prime is 21444541. The reversal of 21444521 is 12544412.

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

It is a cyclic number.

It is not a de Polignac number, because 21444521 - 2⁶ = 21444457 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21444541) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 80486 + ... + 80751.

It is an arithmetic number, because the mean of its divisors is an integer number (3224760).

Almost surely, 2^21444521 is an apocalyptic number.

It is an amenable number.

21444521 is a deficient number, since it is larger than the sum of its proper divisors (4353559).

21444521 is a wasteful number, since it uses less digits than its factorization.

21444521 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 161263.

The product of its digits is 1280, while the sum is 23.

The square root of 21444521 is about 4630.8229290268. The cubic root of 21444521 is about 277.8255077034.

Adding to 21444521 its reverse (12544412), we get a palindrome (33988933).

The spelling of 21444521 in words is "twenty-one million, four hundred forty-four thousand, five hundred twenty-one".