21223043 has 4 divisors (see below), whose sum is σ = 22145808. Its totient is φ = 20300280.

The previous prime is 21223009. The next prime is 21223051. The reversal of 21223043 is 34032212.

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 21223043 - 2⁶ = 21222979 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21223073) 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, 461348 + ... + 461393.

It is an arithmetic number, because the mean of its divisors is an integer number (5536452).

Almost surely, 2^21223043 is an apocalyptic number.

21223043 is a gapful number since it is divisible by the number (23) formed by its first and last digit.

21223043 is a deficient number, since it is larger than the sum of its proper divisors (922765).

21223043 is an equidigital number, since it uses as much as digits as its factorization.

21223043 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 922764.

The product of its (nonzero) digits is 288, while the sum is 17.

The square root of 21223043 is about 4606.8474035939. The cubic root of 21223043 is about 276.8657396941.

Adding to 21223043 its reverse (34032212), we get a palindrome (55255255).

The spelling of 21223043 in words is "twenty-one million, two hundred twenty-three thousand, forty-three".