21231232 has 64 divisors (see below), whose sum is σ = 48911040. Its totient is φ = 9072640.

The previous prime is 21231173. The next prime is 21231241. The reversal of 21231232 is 23213212.

It is a tau number, because it is divible by the number of its divisors (64).

It is a Harshad number since it is a multiple of its sum of digits (16).

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 23493 + ... + 24379.

It is an arithmetic number, because the mean of its divisors is an integer number (764235).

Almost surely, 2^21231232 is an apocalyptic number.

21231232 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 21231232, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (24455520).

21231232 is an abundant number, since it is smaller than the sum of its proper divisors (27679808).

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

21231232 is a wasteful number, since it uses less digits than its factorization.

21231232 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 929 (or 917 counting only the distinct ones).

The product of its digits is 144, while the sum is 16.

The square root of 21231232 is about 4607.7361035545. The cubic root of 21231232 is about 276.9013450499.

Adding to 21231232 its reverse (23213212), we get a palindrome (44444444).

The spelling of 21231232 in words is "twenty-one million, two hundred thirty-one thousand, two hundred thirty-two".