21045443 has 4 divisors (see below), whose sum is σ = 21060048. Its totient is φ = 21030840.

The previous prime is 21045433. The next prime is 21045457. The reversal of 21045443 is 34454012.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 21045443 - 2¹⁴ = 21029059 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21045433) 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, 4871 + ... + 8112.

It is an arithmetic number, because the mean of its divisors is an integer number (5265012).

Almost surely, 2^21045443 is an apocalyptic number.

21045443 is a deficient number, since it is larger than the sum of its proper divisors (14605).

21045443 is a wasteful number, since it uses less digits than its factorization.

21045443 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 14604.

The product of its (nonzero) digits is 1920, while the sum is 23.

The square root of 21045443 is about 4587.5312532995. The cubic root of 21045443 is about 276.0912802819.

Adding to 21045443 its reverse (34454012), we get a palindrome (55499455).

The spelling of 21045443 in words is "twenty-one million, forty-five thousand, four hundred forty-three".