21443443 has 16 divisors (see below), whose sum is σ = 26072064. Its totient is φ = 17216640.

The previous prime is 21443437. The next prime is 21443447. The reversal of 21443443 is 34434412.

It is a de Polignac number, because none of the positive numbers 2^k-21443443 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21443447) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 43428 + ... + 43918.

It is an arithmetic number, because the mean of its divisors is an integer number (1629504).

Almost surely, 2^21443443 is an apocalyptic number.

21443443 is a deficient number, since it is larger than the sum of its proper divisors (4628621).

21443443 is a wasteful number, since it uses less digits than its factorization.

21443443 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 882.

The product of its digits is 4608, while the sum is 25.

The square root of 21443443 is about 4630.7065335648. The cubic root of 21443443 is about 277.8208522654.

Adding to 21443443 its reverse (34434412), we get a palindrome (55877855).

The spelling of 21443443 in words is "twenty-one million, four hundred forty-three thousand, four hundred forty-three".