20807808 has 64 divisors (see below), whose sum is σ = 63174720. Its totient is φ = 5944320.

The previous prime is 20807803. The next prime is 20807833. The reversal of 20807808 is 80870802.

It is a tau number, because it is divible by the number of its divisors (64).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20807803) 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, 1183 + ... + 6558.

It is an arithmetic number, because the mean of its divisors is an integer number (987105).

Almost surely, 2^20807808 is an apocalyptic number.

20807808 is a gapful number since it is divisible by the number (28) 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 20807808, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (31587360).

20807808 is an abundant number, since it is smaller than the sum of its proper divisors (42366912).

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

20807808 is an equidigital number, since it uses as much as digits as its factorization.

20807808 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7765 (or 7753 counting only the distinct ones).

The product of its (nonzero) digits is 7168, while the sum is 33.

The square root of 20807808 is about 4561.5576287054. The cubic root of 20807808 is about 275.0481810897.

The spelling of 20807808 in words is "twenty million, eight hundred seven thousand, eight hundred eight".