21434423 has 4 divisors (see below), whose sum is σ = 22125888. Its totient is φ = 20742960.

The previous prime is 21434417. The next prime is 21434429. The reversal of 21434423 is 32443412.

It is a semiprime because it is the product of two primes.

It is an interprime number because it is at equal distance from previous prime (21434417) and next prime (21434429).

It is a cyclic number.

It is not a de Polignac number, because 21434423 - 2¹² = 21430327 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21434429) 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 3 ways as a sum of consecutive naturals, for example, 345686 + ... + 345747.

It is an arithmetic number, because the mean of its divisors is an integer number (5531472).

Almost surely, 2^21434423 is an apocalyptic number.

21434423 is a deficient number, since it is larger than the sum of its proper divisors (691465).

21434423 is an equidigital number, since it uses as much as digits as its factorization.

21434423 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 691464.

The product of its digits is 2304, while the sum is 23.

The square root of 21434423 is about 4629.7324976720. The cubic root of 21434423 is about 277.7818924842.

Adding to 21434423 its reverse (32443412), we get a palindrome (53877835).

The spelling of 21434423 in words is "twenty-one million, four hundred thirty-four thousand, four hundred twenty-three".