21424361 has 4 divisors (see below), whose sum is σ = 24484992. Its totient is φ = 18363732.

The previous prime is 21424357. The next prime is 21424367. The reversal of 21424361 is 16342412.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 21424361 - 2² = 21424357 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21424367) 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, 1530305 + ... + 1530318.

It is an arithmetic number, because the mean of its divisors is an integer number (6121248).

Almost surely, 2^21424361 is an apocalyptic number.

It is an amenable number.

21424361 is a deficient number, since it is larger than the sum of its proper divisors (3060631).

21424361 is an equidigital number, since it uses as much as digits as its factorization.

21424361 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3060630.

The product of its digits is 1152, while the sum is 23.

The square root of 21424361 is about 4628.6456982578. The cubic root of 21424361 is about 277.7384191287.

Adding to 21424361 its reverse (16342412), we get a palindrome (37766773).

The spelling of 21424361 in words is "twenty-one million, four hundred twenty-four thousand, three hundred sixty-one".