21200664 has 64 divisors (see below), whose sum is σ = 55872000. Its totient is φ = 6690816.

The previous prime is 21200639. The next prime is 21200681. The reversal of 21200664 is 46600212.

It is a happy number.

It is a self number, because there is not a number n which added to its sum of digits gives 21200664.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 106437 + ... + 106635.

It is an arithmetic number, because the mean of its divisors is an integer number (873000).

Almost surely, 2^21200664 is an apocalyptic number.

21200664 is a gapful number since it is divisible by the number (24) 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 21200664, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (27936000).

21200664 is an abundant number, since it is smaller than the sum of its proper divisors (34671336).

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

21200664 is a wasteful number, since it uses less digits than its factorization.

21200664 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 424 (or 420 counting only the distinct ones).

The product of its (nonzero) digits is 576, while the sum is 21.

The square root of 21200664 is about 4604.4178785162. The cubic root of 21200664 is about 276.7683902002.

Adding to 21200664 its reverse (46600212), we get a palindrome (67800876).

The spelling of 21200664 in words is "twenty-one million, two hundred thousand, six hundred sixty-four".