21445443 has 12 divisors (see below), whose sum is σ = 31561920. Its totient is φ = 14026896.

The previous prime is 21445441. The next prime is 21445451. The reversal of 21445443 is 34454412.

It is a happy number.

21445443 is a `hidden beast` number, since 214 + 4 + 5 + 443 = 666.

It is not a de Polignac number, because 21445443 - 2¹ = 21445441 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21445441) 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 11 ways as a sum of consecutive naturals, for example, 22003 + ... + 22956.

It is an arithmetic number, because the mean of its divisors is an integer number (2630160).

Almost surely, 2^21445443 is an apocalyptic number.

21445443 is a deficient number, since it is larger than the sum of its proper divisors (10116477).

21445443 is a wasteful number, since it uses less digits than its factorization.

21445443 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 45018 (or 45015 counting only the distinct ones).

The product of its digits is 7680, while the sum is 27.

The square root of 21445443 is about 4630.9224782974. The cubic root of 21445443 is about 277.8294893179.

Adding to 21445443 its reverse (34454412), we get a palindrome (55899855).

The spelling of 21445443 in words is "twenty-one million, four hundred forty-five thousand, four hundred forty-three".