21104064 has 168 divisors, whose sum is σ = 66568320. Its totient is φ = 6614784.

The previous prime is 21104063. The next prime is 21104071. The reversal of 21104064 is 46040112.

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

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21104063) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 357667 + ... + 357725.

It is an arithmetic number, because the mean of its divisors is an integer number (396240).

Almost surely, 2^21104064 is an apocalyptic number.

21104064 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 21104064, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (33284160).

21104064 is an abundant number, since it is smaller than the sum of its proper divisors (45464256).

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

21104064 is an equidigital number, since it uses as much as digits as its factorization.

21104064 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 109 (or 87 counting only the distinct ones).

The product of its (nonzero) digits is 192, while the sum is 18.

The square root of 21104064 is about 4593.9159765934. The cubic root of 21104064 is about 276.3473886612.

Adding to 21104064 its reverse (46040112), we get a palindrome (67144176).

The spelling of 21104064 in words is "twenty-one million, one hundred four thousand, sixty-four".