20561472 has 112 divisors (see below), whose sum is σ = 61650880. Its totient is φ = 6718464.

The previous prime is 20561467. The next prime is 20561473. The reversal of 20561472 is 27416502.

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

It is not an unprimeable number, because it can be changed into a prime (20561473) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 126063 + ... + 126225.

Almost surely, 2^20561472 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 20561472, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (30825440).

20561472 is an abundant number, since it is smaller than the sum of its proper divisors (41089408).

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

20561472 is a wasteful number, since it uses less digits than its factorization.

20561472 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 257 (or 241 counting only the distinct ones).

The product of its (nonzero) digits is 3360, while the sum is 27.

The square root of 20561472 is about 4534.4759344383. The cubic root of 20561472 is about 273.9584713376.

Adding to 20561472 its reverse (27416502), we get a palindrome (47977974).

The spelling of 20561472 in words is "twenty million, five hundred sixty-one thousand, four hundred seventy-two".