21231132 has 108 divisors (see below), whose sum is σ = 58567320. Its totient is φ = 5975424.

The previous prime is 21231107. The next prime is 21231143. The reversal of 21231132 is 23113212.

It is a nude number because it is divisible by every one of its digits.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 35 ways as a sum of consecutive naturals, for example, 732094 + ... + 732122.

It is an arithmetic number, because the mean of its divisors is an integer number (542290).

Almost surely, 2^21231132 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 21231132, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (29283660).

21231132 is an abundant number, since it is smaller than the sum of its proper divisors (37336188).

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

21231132 is a wasteful number, since it uses less digits than its factorization.

21231132 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 100 (or 66 counting only the distinct ones).

The product of its digits is 72, while the sum is 15.

The square root of 21231132 is about 4607.7252522259. The cubic root of 21231132 is about 276.9009103102.

Adding to 21231132 its reverse (23113212), we get a palindrome (44344344).

The spelling of 21231132 in words is "twenty-one million, two hundred thirty-one thousand, one hundred thirty-two".