21212432 has 20 divisors (see below), whose sum is σ = 42425856. Its totient is φ = 10263840.

The previous prime is 21212431. The next prime is 21212449. The reversal of 21212432 is 23421212.

21212432 is an admirable number.

It is a self number, because there is not a number n which added to its sum of digits gives 21212432.

It is not an unprimeable number, because it can be changed into a prime (21212431) 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, 20888 + ... + 21879.

Almost surely, 2^21212432 is an apocalyptic number.

It is an amenable number.

21212432 is a primitive abundant number, since it is smaller than the sum of its proper divisors, none of which is abundant.

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

21212432 is a wasteful number, since it uses less digits than its factorization.

21212432 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 42806 (or 42800 counting only the distinct ones).

The product of its digits is 192, while the sum is 17.

The square root of 21212432 is about 4605.6956043577. The cubic root of 21212432 is about 276.8195899798.

Adding to 21212432 its reverse (23421212), we get a palindrome (44633644).

The spelling of 21212432 in words is "twenty-one million, two hundred twelve thousand, four hundred thirty-two".