21452423 has 4 divisors (see below), whose sum is σ = 21673680. Its totient is φ = 21231168.

The previous prime is 21452413. The next prime is 21452443. The reversal of 21452423 is 32425412.

It is a happy number.

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 21452423 - 2⁴ = 21452407 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21452413) 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, 110483 + ... + 110676.

It is an arithmetic number, because the mean of its divisors is an integer number (5418420).

Almost surely, 2^21452423 is an apocalyptic number.

21452423 is a deficient number, since it is larger than the sum of its proper divisors (221257).

21452423 is an equidigital number, since it uses as much as digits as its factorization.

21452423 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 221256.

The product of its digits is 1920, while the sum is 23.

The square root of 21452423 is about 4631.6760465300. The cubic root of 21452423 is about 277.8596284245.

Adding to 21452423 its reverse (32425412), we get a palindrome (53877835).

The spelling of 21452423 in words is "twenty-one million, four hundred fifty-two thousand, four hundred twenty-three".