21424147 has 8 divisors (see below), whose sum is σ = 22136976. Its totient is φ = 20718432.

The previous prime is 21424129. The next prime is 21424159. The reversal of 21424147 is 74142412.

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

It is a cyclic number.

It is not a de Polignac number, because 21424147 - 2¹¹ = 21422099 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21424547) 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, 4728 + ... + 8074.

It is an arithmetic number, because the mean of its divisors is an integer number (2767122).

Almost surely, 2^21424147 is an apocalyptic number.

21424147 is a deficient number, since it is larger than the sum of its proper divisors (712829).

21424147 is a wasteful number, since it uses less digits than its factorization.

21424147 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3557.

The product of its digits is 1792, while the sum is 25.

The square root of 21424147 is about 4628.6225812870. The cubic root of 21424147 is about 277.7374943836.

Adding to 21424147 its reverse (74142412), we get a palindrome (95566559).

The spelling of 21424147 in words is "twenty-one million, four hundred twenty-four thousand, one hundred forty-seven".