21543479 has 4 divisors (see below), whose sum is σ = 22480176. Its totient is φ = 20606784.

The previous prime is 21543461. The next prime is 21543499. The reversal of 21543479 is 97434512.

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 21543479 - 2²⁴ = 4766263 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 (21543439) 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, 468314 + ... + 468359.

It is an arithmetic number, because the mean of its divisors is an integer number (5620044).

Almost surely, 2^21543479 is an apocalyptic number.

21543479 is a deficient number, since it is larger than the sum of its proper divisors (936697).

21543479 is an equidigital number, since it uses as much as digits as its factorization.

21543479 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 936696.

The product of its digits is 30240, while the sum is 35.

The square root of 21543479 is about 4641.4953409435. The cubic root of 21543479 is about 278.2522037160.

It can be divided in two parts, 21543 and 479, that added together give a palindrome (22022).

The spelling of 21543479 in words is "twenty-one million, five hundred forty-three thousand, four hundred seventy-nine".