21432832 has 40 divisors (see below), whose sum is σ = 43911252. Its totient is φ = 10444800.

The previous prime is 21432821. The next prime is 21432833. The reversal of 21432832 is 23823412.

It can be written as a sum of positive squares in 2 ways, for example, as 20214016 + 1218816 = 4496^2 + 1104^2 .

It is a junction number, because it is equal to n+sod(n) for n = 21432797 and 21432806.

It is not an unprimeable number, because it can be changed into a prime (21432833) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 20482 + ... + 21502.

Almost surely, 2^21432832 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 21432832, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (21955626).

21432832 is an abundant number, since it is smaller than the sum of its proper divisors (22478420).

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

21432832 is an equidigital number, since it uses as much as digits as its factorization.

21432832 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1080 (or 1064 counting only the distinct ones).

The product of its digits is 2304, while the sum is 25.

The square root of 21432832 is about 4629.5606703012. The cubic root of 21432832 is about 277.7750193978.

The spelling of 21432832 in words is "twenty-one million, four hundred thirty-two thousand, eight hundred thirty-two".