20444561 has 4 divisors (see below), whose sum is σ = 20484324. Its totient is φ = 20404800.

The previous prime is 20444519. The next prime is 20444569. The reversal of 20444561 is 16544402.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 5382400 + 15062161 = 2320^2 + 3881^2 .

It is a cyclic number.

It is not a de Polignac number, because 20444561 - 2⁶ = 20444497 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 20444561.

It is not an unprimeable number, because it can be changed into a prime (20444569) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 19100 + ... + 20141.

It is an arithmetic number, because the mean of its divisors is an integer number (5121081).

Almost surely, 2^20444561 is an apocalyptic number.

It is an amenable number.

20444561 is a deficient number, since it is larger than the sum of its proper divisors (39763).

20444561 is an equidigital number, since it uses as much as digits as its factorization.

20444561 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 39762.

The product of its (nonzero) digits is 3840, while the sum is 26.

The square root of 20444561 is about 4521.5662109495. The cubic root of 20444561 is about 273.4382482766.

Adding to 20444561 its reverse (16544402), we get a palindrome (36988963).

The spelling of 20444561 in words is "twenty million, four hundred forty-four thousand, five hundred sixty-one".