20561200 has 60 divisors (see below), whose sum is σ = 53900568. Its totient is φ = 7475200.

The previous prime is 20561179. The next prime is 20561201. The reversal of 20561200 is 216502.

It is a happy number.

It is a Harshad number since it is a multiple of its sum of digits (16).

It is not an unprimeable number, because it can be changed into a prime (20561201) 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 11 ways as a sum of consecutive naturals, for example, 2064 + ... + 6736.

Almost surely, 2^20561200 is an apocalyptic number.

20561200 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 20561200, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (26950284).

20561200 is an abundant number, since it is smaller than the sum of its proper divisors (33339368).

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

20561200 is a wasteful number, since it uses less digits than its factorization.

20561200 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4702 (or 4691 counting only the distinct ones).

The product of its (nonzero) digits is 120, while the sum is 16.

The square root of 20561200 is about 4534.4459418985. The cubic root of 20561200 is about 273.9572633010.

Adding to 20561200 its reverse (216502), we get a palindrome (20777702).

The spelling of 20561200 in words is "twenty million, five hundred sixty-one thousand, two hundred".