21250424 has 16 divisors (see below), whose sum is σ = 42909720. Its totient is φ = 9807840.

The previous prime is 21250399. The next prime is 21250429. The reversal of 21250424 is 42405212.

It is a happy number.

It is a junction number, because it is equal to n+sod(n) for n = 21250396 and 21250405.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21250429) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 102062 + ... + 102269.

Almost surely, 2^21250424 is an apocalyptic number.

It is an amenable number.

21250424 is an abundant number, since it is smaller than the sum of its proper divisors (21659296).

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

21250424 is a wasteful number, since it uses less digits than its factorization.

21250424 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 204350 (or 204346 counting only the distinct ones).

The product of its (nonzero) digits is 640, while the sum is 20.

The square root of 21250424 is about 4609.8182176741. The cubic root of 21250424 is about 276.9847550334.

Adding to 21250424 its reverse (42405212), we get a palindrome (63655636).

The spelling of 21250424 in words is "twenty-one million, two hundred fifty thousand, four hundred twenty-four".