21328104 has 64 divisors (see below), whose sum is σ = 61747200. Its totient is φ = 6012864.

The previous prime is 21328103. The next prime is 21328117. The reversal of 21328104 is 40182312.

It is a Harshad number since it is a multiple of its sum of digits (21).

It is not an unprimeable number, because it can be changed into a prime (21328103) 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 15 ways as a sum of consecutive naturals, for example, 12469 + ... + 14075.

It is an arithmetic number, because the mean of its divisors is an integer number (964800).

Almost surely, 2^21328104 is an apocalyptic number.

21328104 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 21328104, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (30873600).

21328104 is an abundant number, since it is smaller than the sum of its proper divisors (40419096).

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

21328104 is a wasteful number, since it uses less digits than its factorization.

21328104 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1702 (or 1698 counting only the distinct ones).

The product of its (nonzero) digits is 384, while the sum is 21.

The square root of 21328104 is about 4618.2360268830. The cubic root of 21328104 is about 277.3218465307.

The spelling of 21328104 in words is "twenty-one million, three hundred twenty-eight thousand, one hundred four".