21424305 has 32 divisors (see below), whose sum is σ = 41241600. Its totient is φ = 9277632.

The previous prime is 21424303. The next prime is 21424313. The reversal of 21424305 is 50342412.

It is not a de Polignac number, because 21424305 - 2¹ = 21424303 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (21).

It is not an unprimeable number, because it can be changed into a prime (21424303) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 3375 + ... + 7364.

It is an arithmetic number, because the mean of its divisors is an integer number (1288800).

Almost surely, 2^21424305 is an apocalyptic number.

It is an amenable number.

21424305 is a deficient number, since it is larger than the sum of its proper divisors (19817295).

21424305 is a wasteful number, since it uses less digits than its factorization.

21424305 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10773.

The product of its (nonzero) digits is 960, while the sum is 21.

The square root of 21424305 is about 4628.6396489682. The cubic root of 21424305 is about 277.7381771399.

Adding to 21424305 its reverse (50342412), we get a palindrome (71766717).

The spelling of 21424305 in words is "twenty-one million, four hundred twenty-four thousand, three hundred five".