21648080 has 20 divisors (see below), whose sum is σ = 50331972. Its totient is φ = 8659200.

The previous prime is 21648079. The next prime is 21648127. The reversal of 21648080 is 8084612.

It can be written as a sum of positive squares in 2 ways, for example, as 11888704 + 9759376 = 3448^2 + 3124^2 .

It is a tau number, because it is divible by the number of its divisors (20).

It is a Smith number, since the sum of its digits (29) coincides with the sum of the digits of its prime factors.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 135221 + ... + 135380.

Almost surely, 2^21648080 is an apocalyptic number.

21648080 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21648080 is an abundant number, since it is smaller than the sum of its proper divisors (28683892).

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

21648080 is a wasteful number, since it uses less digits than its factorization.

21648080 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 270614 (or 270608 counting only the distinct ones).

The product of its (nonzero) digits is 3072, while the sum is 29.

The square root of 21648080 is about 4652.7497246252. The cubic root of 21648080 is about 278.7018135452.

The spelling of 21648080 in words is "twenty-one million, six hundred forty-eight thousand, eighty".