21204000 has 288 divisors, whose sum is σ = 81768960. Its totient is φ = 5184000.

The previous prime is 21203977. The next prime is 21204013. The reversal of 21204000 is 40212.

It is a tau number, because it is divible by the number of its divisors (288).

It is a Harshad number since it is a multiple of its sum of digits (9).

It is an unprimeable number.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 683985 + ... + 684015.

It is an arithmetic number, because the mean of its divisors is an integer number (283920).

Almost surely, 2^21204000 is an apocalyptic number.

21204000 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 21204000, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (40884480).

21204000 is an abundant number, since it is smaller than the sum of its proper divisors (60564960).

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

21204000 is a wasteful number, since it uses less digits than its factorization.

21204000 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 81 (or 60 counting only the distinct ones).

The product of its (nonzero) digits is 16, while the sum is 9.

The square root of 21204000 is about 4604.7801250440. The cubic root of 21204000 is about 276.7829062695.

Adding to 21204000 its reverse (40212), we get a palindrome (21244212).

The spelling of 21204000 in words is "twenty-one million, two hundred four thousand".