20009808 has 160 divisors (see below), whose sum is σ = 70828800. Its totient is φ = 5266944.

The previous prime is 20009761. The next prime is 20009813. The reversal of 20009808 is 80890002.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 39058 + ... + 39566.

It is an arithmetic number, because the mean of its divisors is an integer number (442680).

Almost surely, 2^20009808 is an apocalyptic number.

20009808 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 20009808, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (35414400).

20009808 is an abundant number, since it is smaller than the sum of its proper divisors (50818992).

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

20009808 is a wasteful number, since it uses less digits than its factorization.

20009808 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 546 (or 534 counting only the distinct ones).

The product of its (nonzero) digits is 1152, while the sum is 27.

The square root of 20009808 is about 4473.2323883295. The cubic root of 20009808 is about 271.4861260881.

The spelling of 20009808 in words is "twenty million, nine thousand, eight hundred eight".