20808320 has 128 divisors (see below), whose sum is σ = 55777680. Its totient is φ = 7372800.

The previous prime is 20808317. The next prime is 20808373. The reversal of 20808320 is 2380802.

It can be written as a sum of positive squares in 8 ways, for example, as 87616 + 20720704 = 296^2 + 4552^2 .

It is a tau number, because it is divible by the number of its divisors (128).

It is a hoax number, since the sum of its digits (23) coincides with the sum of the digits of its distinct prime factors.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 341090 + ... + 341150.

Almost surely, 2^20808320 is an apocalyptic number.

20808320 is a gapful number since it is divisible by the number (20) 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 20808320, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (27888840).

20808320 is an abundant number, since it is smaller than the sum of its proper divisors (34969360).

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

20808320 is a wasteful number, since it uses less digits than its factorization.

20808320 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 134 (or 122 counting only the distinct ones).

The product of its (nonzero) digits is 768, while the sum is 23.

The square root of 20808320 is about 4561.6137495408. The cubic root of 20808320 is about 275.0504370299.

It can be divided in two parts, 2080 and 8320, that multiplied together give a square (17305600 = 4160²).

The spelling of 20808320 in words is "twenty million, eight hundred eight thousand, three hundred twenty".