21024424 has 8 divisors (see below), whose sum is σ = 39420810. Its totient is φ = 10512208.

The previous prime is 21024413. The next prime is 21024433. The reversal of 21024424 is 42442012.

It can be written as a sum of positive squares in only one way, i.e., 19201924 + 1822500 = 4382^2 + 1350^2 .

It is a tau number, because it is divible by the number of its divisors (8).

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1314019 + ... + 1314034.

Almost surely, 2^21024424 is an apocalyptic number.

It is an amenable number.

21024424 is a deficient number, since it is larger than the sum of its proper divisors (18396386).

21024424 is a wasteful number, since it uses less digits than its factorization.

21024424 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2628059 (or 2628055 counting only the distinct ones).

The product of its (nonzero) digits is 512, while the sum is 19.

The square root of 21024424 is about 4585.2397974370. The cubic root of 21024424 is about 275.9993348720. Note that the first 3 decimals are identical.

Adding to 21024424 its reverse (42442012), we get a palindrome (63466436).

The spelling of 21024424 in words is "twenty-one million, twenty-four thousand, four hundred twenty-four".