20209560 has 128 divisors (see below), whose sum is σ = 70848000. Its totient is φ = 4609920.

The previous prime is 20209547. The next prime is 20209561. The reversal of 20209560 is 6590202.

It is a Harshad number since it is a multiple of its sum of digits (24).

It is a self number, because there is not a number n which added to its sum of digits gives 20209560.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20209561) by changing a digit.

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 31 ways as a sum of consecutive naturals, for example, 40915 + ... + 41405.

It is an arithmetic number, because the mean of its divisors is an integer number (553500).

Almost surely, 2^20209560 is an apocalyptic number.

20209560 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 20209560, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (35424000).

20209560 is an abundant number, since it is smaller than the sum of its proper divisors (50638440).

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

20209560 is a wasteful number, since it uses less digits than its factorization.

20209560 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 526 (or 508 counting only the distinct ones).

The product of its (nonzero) digits is 1080, while the sum is 24.

The square root of 20209560 is about 4495.5044210856. The cubic root of 20209560 is about 272.3865251517.

Adding to 20209560 its reverse (6590202), we get a palindrome (26799762).

The spelling of 20209560 in words is "twenty million, two hundred nine thousand, five hundred sixty".