20804220 has 72 divisors (see below), whose sum is σ = 64668240. Its totient is φ = 5410560.

The previous prime is 20804159. The next prime is 20804257. The reversal of 20804220 is 2240802.

It is a Harshad number since it is a multiple of its sum of digits (18).

It is a junction number, because it is equal to n+sod(n) for n = 20804193 and 20804202.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 5971 + ... + 8789.

It is an arithmetic number, because the mean of its divisors is an integer number (898170).

Almost surely, 2^20804220 is an apocalyptic number.

20804220 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 20804220, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (32334120).

20804220 is an abundant number, since it is smaller than the sum of its proper divisors (43864020).

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

20804220 is a wasteful number, since it uses less digits than its factorization.

20804220 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2875 (or 2870 counting only the distinct ones).

The product of its (nonzero) digits is 256, while the sum is 18.

The square root of 20804220 is about 4561.1643250381. The cubic root of 20804220 is about 275.0323708451.

The spelling of 20804220 in words is "twenty million, eight hundred four thousand, two hundred twenty".