21031332 has 48 divisors (see below), whose sum is σ = 56622720. Its totient is φ = 5951232.

The previous prime is 21031313. The next prime is 21031333. The reversal of 21031332 is 23313012.

It is not an unprimeable number, because it can be changed into a prime (21031333) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 8008 + ... + 10304.

It is an arithmetic number, because the mean of its divisors is an integer number (1179640).

Almost surely, 2^21031332 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 21031332, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (28311360).

21031332 is an abundant number, since it is smaller than the sum of its proper divisors (35591388).

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

21031332 is a wasteful number, since it uses less digits than its factorization.

21031332 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2420 (or 2418 counting only the distinct ones).

The product of its (nonzero) digits is 108, while the sum is 15.

The square root of 21031332 is about 4585.9930222363. The cubic root of 21031332 is about 276.0295599510.

Adding to 21031332 its reverse (23313012), we get a palindrome (44344344).

The spelling of 21031332 in words is "twenty-one million, thirty-one thousand, three hundred thirty-two".