21030016 has 64 divisors (see below), whose sum is σ = 48960000. Its totient is φ = 8994048.

The previous prime is 21030001. The next prime is 21030043. The reversal of 21030016 is 61003012.

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

It is a junction number, because it is equal to n+sod(n) for n = 21029978 and 21030005.

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 7 ways as a sum of consecutive naturals, for example, 43665 + ... + 44143.

It is an arithmetic number, because the mean of its divisors is an integer number (765000).

Almost surely, 2^21030016 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 21030016, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (24480000).

21030016 is an abundant number, since it is smaller than the sum of its proper divisors (27929984).

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

21030016 is an frugal number, since it uses more digits than its factorization.

21030016 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 514 (or 488 counting only the distinct ones).

The product of its (nonzero) digits is 36, while the sum is 13.

The square root of 21030016 is about 4585.8495396164. The cubic root of 21030016 is about 276.0238024701.

Adding to 21030016 its reverse (61003012), we get a palindrome (82033028).

The spelling of 21030016 in words is "twenty-one million, thirty thousand, sixteen".