21071232 has 256 divisors, whose sum is σ = 77683200. Its totient is φ = 5474304.

The previous prime is 21071221. The next prime is 21071249. The reversal of 21071232 is 23217012.

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

It is a congruent number.

It is an unprimeable number.

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 31 ways as a sum of consecutive naturals, for example, 314463 + ... + 314529.

It is an arithmetic number, because the mean of its divisors is an integer number (303450).

Almost surely, 2^21071232 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 21071232, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (38841600).

21071232 is an abundant number, since it is smaller than the sum of its proper divisors (56611968).

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

21071232 is a wasteful number, since it uses less digits than its factorization.

21071232 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 110 (or 92 counting only the distinct ones).

The product of its (nonzero) digits is 168, while the sum is 18.

The square root of 21071232 is about 4590.3411637916. The cubic root of 21071232 is about 276.2040079586.

Adding to 21071232 its reverse (23217012), we get a palindrome (44288244).

The spelling of 21071232 in words is "twenty-one million, seventy-one thousand, two hundred thirty-two".