21063600 has 90 divisors (see below), whose sum is σ = 73109036. Its totient is φ = 5616000.

The previous prime is 21063569. The next prime is 21063673. The reversal of 21063600 is 636012.

It is a happy number.

21063600 is a `hidden beast` number, since 2 + 1 + 0 + 63 + 600 = 666.

It is a tau number, because it is divible by the number of its divisors (90).

It is a Harshad number since it is a multiple of its sum of digits (18).

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 17 ways as a sum of consecutive naturals, for example, 675 + ... + 6525.

Almost surely, 2^21063600 is an apocalyptic number.

21063600 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 21063600, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (36554518).

21063600 is an abundant number, since it is smaller than the sum of its proper divisors (52045436).

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

21063600 is a wasteful number, since it uses less digits than its factorization.

21063600 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5875 (or 5861 counting only the distinct ones).

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

The square root of 21063600 is about 4589.5097777432. The cubic root of 21063600 is about 276.1706569022.

Adding to 21063600 its reverse (636012), we get a palindrome (21699612).

The spelling of 21063600 in words is "twenty-one million, sixty-three thousand, six hundred".