21189600 has 216 divisors, whose sum is σ = 78198120. Its totient is φ = 5598720.

The previous prime is 21189593. The next prime is 21189607. The reversal of 21189600 is 698112.

It is an interprime number because it is at equal distance from previous prime (21189593) and next prime (21189607).

It is a tau number, because it is divible by the number of its divisors (216).

It is a Harshad number since it is a multiple of its sum of digits (27).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21189607) by changing a digit.

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 35 ways as a sum of consecutive naturals, for example, 194346 + ... + 194454.

Almost surely, 2^21189600 is an apocalyptic number.

21189600 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 21189600, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (39099060).

21189600 is an abundant number, since it is smaller than the sum of its proper divisors (57008520).

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

21189600 is a wasteful number, since it uses less digits than its factorization.

21189600 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 144 (or 119 counting only the distinct ones).

The product of its (nonzero) digits is 864, while the sum is 27.

The square root of 21189600 is about 4603.2162669160. The cubic root of 21189600 is about 276.7202360746.

The spelling of 21189600 in words is "twenty-one million, one hundred eighty-nine thousand, six hundred".