21424330 has 16 divisors (see below), whose sum is σ = 39894120. Its totient is φ = 8274112.

The previous prime is 21424327. The next prime is 21424357. The reversal of 21424330 is 3342412.

It can be written as a sum of positive squares in 4 ways, for example, as 13623481 + 7800849 = 3691^2 + 2793^2 .

It is a junction number, because it is equal to n+sod(n) for n = 21424298 and 21424307.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 36649 + ... + 37228.

Almost surely, 2^21424330 is an apocalyptic number.

21424330 is a deficient number, since it is larger than the sum of its proper divisors (18469790).

21424330 is a wasteful number, since it uses less digits than its factorization.

21424330 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 73913.

The product of its (nonzero) digits is 576, while the sum is 19.

The square root of 21424330 is about 4628.6423495448. The cubic root of 21424330 is about 277.7382851707.

Adding to 21424330 its reverse (3342412), we get a palindrome (24766742).

The spelling of 21424330 in words is "twenty-one million, four hundred twenty-four thousand, three hundred thirty".