21080064 has 96 divisors (see below), whose sum is σ = 58181760. Its totient is φ = 6782976.

The previous prime is 21080057. The next prime is 21080069. The reversal of 21080064 is 46008012.

It is a tau number, because it is divible by the number of its divisors (96).

It is a self number, because there is not a number n which added to its sum of digits gives 21080064.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21080069) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 288732 + ... + 288804.

It is an arithmetic number, because the mean of its divisors is an integer number (606060).

Almost surely, 2^21080064 is an apocalyptic number.

21080064 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 21080064, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (29090880).

21080064 is an abundant number, since it is smaller than the sum of its proper divisors (37101696).

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

21080064 is an equidigital number, since it uses as much as digits as its factorization.

21080064 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 145 (or 125 counting only the distinct ones).

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

The square root of 21080064 is about 4591.3030830038. The cubic root of 21080064 is about 276.2425928414.

Adding to 21080064 its reverse (46008012), we get a palindrome (67088076).

The spelling of 21080064 in words is "twenty-one million, eighty thousand, sixty-four".