21004360 has 64 divisors (see below), whose sum is σ = 52577280. Its totient is φ = 7499520.

The previous prime is 21004351. The next prime is 21004387. The reversal of 21004360 is 6340012.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (5) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 15469 + ... + 16771.

It is an arithmetic number, because the mean of its divisors is an integer number (821520).

Almost surely, 2^21004360 is an apocalyptic number.

21004360 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21004360, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (26288640).

21004360 is an abundant number, since it is smaller than the sum of its proper divisors (31572920).

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

21004360 is a wasteful number, since it uses less digits than its factorization.

21004360 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1358 (or 1354 counting only the distinct ones).

The product of its (nonzero) digits is 144, while the sum is 16.

The square root of 21004360 is about 4583.0513852672. The cubic root of 21004360 is about 275.9115098239.

Adding to 21004360 its reverse (6340012), we get a palindrome (27344372).

The spelling of 21004360 in words is "twenty-one million, four thousand, three hundred sixty".