21234423 has 8 divisors (see below), whose sum is σ = 32357248. Its totient is φ = 12133944.

The previous prime is 21234401. The next prime is 21234427. The reversal of 21234423 is 32443212.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 21234423 - 2⁵ = 21234391 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (21), and also a Moran number because the ratio is a prime number: 1011163 = 21234423 / (2 + 1 + 2 + 3 + 4 + 4 + 2 + 3).

It is a self number, because there is not a number n which added to its sum of digits gives 21234423.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21234427) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 505561 + ... + 505602.

It is an arithmetic number, because the mean of its divisors is an integer number (4044656).

Almost surely, 2^21234423 is an apocalyptic number.

21234423 is a deficient number, since it is larger than the sum of its proper divisors (11122825).

21234423 is a wasteful number, since it uses less digits than its factorization.

21234423 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1011173.

The product of its digits is 1152, while the sum is 21.

The square root of 21234423 is about 4608.0823560349. The cubic root of 21234423 is about 276.9152168769.

Adding to 21234423 its reverse (32443212), we get a palindrome (53677635).

The spelling of 21234423 in words is "twenty-one million, two hundred thirty-four thousand, four hundred twenty-three".