21144424 has 32 divisors (see below), whose sum is σ = 45460800. Its totient is φ = 9031680.

The previous prime is 21144419. The next prime is 21144437. The reversal of 21144424 is 42444112.

It is a nude number because it is divisible by every one of its digits.

It is a junction number, because it is equal to n+sod(n) for n = 21144395 and 21144404.

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, 27112 + ... + 27880.

It is an arithmetic number, because the mean of its divisors is an integer number (1420650).

Almost surely, 2^21144424 is an apocalyptic number.

It is an amenable number.

21144424 is an abundant number, since it is smaller than the sum of its proper divisors (24316376).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21144424 is a wasteful number, since it uses less digits than its factorization.

21144424 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1273 (or 1269 counting only the distinct ones).

The product of its digits is 1024, while the sum is 22.

The square root of 21144424 is about 4598.3066448422. The cubic root of 21144424 is about 276.5234412948.

Adding to 21144424 its reverse (42444112), we get a palindrome (63588536).

The spelling of 21144424 in words is "twenty-one million, one hundred forty-four thousand, four hundred twenty-four".