21226043 has 4 divisors (see below), whose sum is σ = 21242160. Its totient is φ = 21209928.

The previous prime is 21226039. The next prime is 21226063. The reversal of 21226043 is 34062212.

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 21226043 - 2² = 21226039 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21226063) 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 3 ways as a sum of consecutive naturals, for example, 5888 + ... + 8781.

It is an arithmetic number, because the mean of its divisors is an integer number (5310540).

Almost surely, 2^21226043 is an apocalyptic number.

21226043 is a deficient number, since it is larger than the sum of its proper divisors (16117).

21226043 is a wasteful number, since it uses less digits than its factorization.

21226043 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 16116.

The product of its (nonzero) digits is 576, while the sum is 20.

The square root of 21226043 is about 4607.1729943643. The cubic root of 21226043 is about 276.8787846045.

Adding to 21226043 its reverse (34062212), we get a palindrome (55288255).

The spelling of 21226043 in words is "twenty-one million, two hundred twenty-six thousand, forty-three".