21143232 has 168 divisors, whose sum is σ = 68470272. Its totient is φ = 6182400.

The previous prime is 21143207. The next prime is 21143251. The reversal of 21143232 is 23234112.

It is a Harshad number since it is a multiple of its sum of digits (18).

It is a nude number because it is divisible by every one of its digits and also a Zuckerman number because it is divisible by the product of its digits.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 297757 + ... + 297827.

Almost surely, 2^21143232 is an apocalyptic number.

21143232 is a gapful number since it is divisible by the number (22) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21143232, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (34235136).

21143232 is an abundant number, since it is smaller than the sum of its proper divisors (47327040).

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

21143232 is a wasteful number, since it uses less digits than its factorization.

21143232 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 147 (or 134 counting only the distinct ones).

The product of its digits is 288, while the sum is 18.

The square root of 21143232 is about 4598.1770300849. The cubic root of 21143232 is about 276.5182449345.

Adding to 21143232 its reverse (23234112), we get a palindrome (44377344).

The spelling of 21143232 in words is "twenty-one million, one hundred forty-three thousand, two hundred thirty-two".