21443549 has 4 divisors (see below), whose sum is σ = 21644064. Its totient is φ = 21243036.

The previous prime is 21443519. The next prime is 21443561. The reversal of 21443549 is 94534412.

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 not a de Polignac number, because 21443549 - 2¹⁶ = 21378013 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21443509) 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, 100097 + ... + 100310.

It is an arithmetic number, because the mean of its divisors is an integer number (5411016).

Almost surely, 2^21443549 is an apocalyptic number.

It is an amenable number.

21443549 is a deficient number, since it is larger than the sum of its proper divisors (200515).

21443549 is a wasteful number, since it uses less digits than its factorization.

21443549 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 200514.

The product of its digits is 17280, while the sum is 32.

The square root of 21443549 is about 4630.7179788884. The cubic root of 21443549 is about 277.8213100426.

The spelling of 21443549 in words is "twenty-one million, four hundred forty-three thousand, five hundred forty-nine".