21234403 has 4 divisors (see below), whose sum is σ = 21243888. Its totient is φ = 21224920.

The previous prime is 21234401. The next prime is 21234427. The reversal of 21234403 is 30443212.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length.

It is a cyclic number.

It is not a de Polignac number, because 21234403 - 2¹ = 21234401 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21234401) 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, 693 + ... + 6553.

It is an arithmetic number, because the mean of its divisors is an integer number (5310972).

Almost surely, 2^21234403 is an apocalyptic number.

21234403 is a deficient number, since it is larger than the sum of its proper divisors (9485).

21234403 is an equidigital number, since it uses as much as digits as its factorization.

21234403 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9484.

The product of its (nonzero) digits is 576, while the sum is 19.

The square root of 21234403 is about 4608.0801859343. The cubic root of 21234403 is about 276.9151299377.

Adding to 21234403 its reverse (30443212), we get a palindrome (51677615).

The spelling of 21234403 in words is "twenty-one million, two hundred thirty-four thousand, four hundred three".