20809548 has 72 divisors (see below), whose sum is σ = 55444480. Its totient is φ = 6823440.

The previous prime is 20809493. The next prime is 20809553. The reversal of 20809548 is 84590802.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 76653 + ... + 76923.

Almost surely, 2^20809548 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 20809548, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (27722240).

20809548 is an abundant number, since it is smaller than the sum of its proper divisors (34634932).

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

20809548 is a wasteful number, since it uses less digits than its factorization.

20809548 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 369 (or 355 counting only the distinct ones).

The product of its (nonzero) digits is 23040, while the sum is 36.

The square root of 20809548 is about 4561.7483490434. The cubic root of 20809548 is about 275.0558476107.

It can be divided in two parts, 2080 and 9548, that added together give a triangular number (11628 = T₁₅₂).

The spelling of 20809548 in words is "twenty million, eight hundred nine thousand, five hundred forty-eight".