21211424 has 24 divisors (see below), whose sum is σ = 44973180. Its totient is φ = 9789696.

The previous prime is 21211403. The next prime is 21211433. The reversal of 21211424 is 42411212.

It can be written as a sum of positive squares in 2 ways, for example, as 20539024 + 672400 = 4532^2 + 820^2 .

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

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 25079 + ... + 25910.

Almost surely, 2^21211424 is an apocalyptic number.

It is an amenable number.

21211424 is an abundant number, since it is smaller than the sum of its proper divisors (23761756).

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

21211424 is a wasteful number, since it uses less digits than its factorization.

21211424 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 51012 (or 51004 counting only the distinct ones).

The product of its digits is 128, while the sum is 17.

The square root of 21211424 is about 4605.5861733334. The cubic root of 21211424 is about 276.8152051522.

Adding to 21211424 its reverse (42411212), we get a palindrome (63622636).

The spelling of 21211424 in words is "twenty-one million, two hundred eleven thousand, four hundred twenty-four".