21434472 has 96 divisors (see below), whose sum is σ = 61031880. Its totient is φ = 6789120.

The previous prime is 21434471. The next prime is 21434531. The reversal of 21434472 is 27443412.

21434472 is a `hidden beast` number, since 214 + 3 + 447 + 2 = 666.

It can be written as a sum of positive squares in 4 ways, for example, as 16208676 + 5225796 = 4026^2 + 2286^2 .

It is a zygodrome in base 11.

It is not an unprimeable number, because it can be changed into a prime (21434471) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 156388 + ... + 156524.

Almost surely, 2^21434472 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21434472, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (30515940).

21434472 is an abundant number, since it is smaller than the sum of its proper divisors (39597408).

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

21434472 is a wasteful number, since it uses less digits than its factorization.

21434472 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 243 (or 236 counting only the distinct ones).

The product of its digits is 5376, while the sum is 27.

The square root of 21434472 is about 4629.7377895514. The cubic root of 21434472 is about 277.7821041578.

Adding to 21434472 its reverse (27443412), we get a palindrome (48877884).

The spelling of 21434472 in words is "twenty-one million, four hundred thirty-four thousand, four hundred seventy-two".