21032316 has 72 divisors (see below), whose sum is σ = 56718480. Its totient is φ = 6552576.

The previous prime is 21032309. The next prime is 21032329. The reversal of 21032316 is 61323012.

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 (13) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 66190 + ... + 66506.

Almost surely, 2^21032316 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 21032316, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (28359240).

21032316 is an abundant number, since it is smaller than the sum of its proper divisors (35686164).

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

21032316 is a wasteful number, since it uses less digits than its factorization.

21032316 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 443 (or 438 counting only the distinct ones).

The product of its (nonzero) digits is 216, while the sum is 18.

The square root of 21032316 is about 4586.1003041800. The cubic root of 21032316 is about 276.0338647798.

Adding to 21032316 its reverse (61323012), we get a palindrome (82355328).

The spelling of 21032316 in words is "twenty-one million, thirty-two thousand, three hundred sixteen".