21456443 has 4 divisors (see below), whose sum is σ = 21478248. Its totient is φ = 21434640.

The previous prime is 21456439. The next prime is 21456469. The reversal of 21456443 is 34465412.

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 21456443 - 2² = 21456439 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21456403) 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, 9353 + ... + 11418.

It is an arithmetic number, because the mean of its divisors is an integer number (5369562).

Almost surely, 2^21456443 is an apocalyptic number.

21456443 is a deficient number, since it is larger than the sum of its proper divisors (21805).

21456443 is a wasteful number, since it uses less digits than its factorization.

21456443 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 21804.

The product of its digits is 11520, while the sum is 29.

The square root of 21456443 is about 4632.1099943762. The cubic root of 21456443 is about 277.8769835106.

The spelling of 21456443 in words is "twenty-one million, four hundred fifty-six thousand, four hundred forty-three".