21116004 has 96 divisors (see below), whose sum is σ = 61829376. Its totient is φ = 5460480.

The previous prime is 21115999. The next prime is 21116059. The reversal of 21116004 is 40061112.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 66454 + ... + 66770.

It is an arithmetic number, because the mean of its divisors is an integer number (644056).

Almost surely, 2^21116004 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 21116004, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (30914688).

21116004 is an abundant number, since it is smaller than the sum of its proper divisors (40713372).

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

21116004 is a wasteful number, since it uses less digits than its factorization.

21116004 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 405 (or 403 counting only the distinct ones).

The product of its (nonzero) digits is 48, while the sum is 15.

The square root of 21116004 is about 4595.2153377181. The cubic root of 21116004 is about 276.3994949877.

Adding to 21116004 its reverse (40061112), we get a palindrome (61177116).

The spelling of 21116004 in words is "twenty-one million, one hundred sixteen thousand, four".