20561045 has 4 divisors (see below), whose sum is σ = 24673260. Its totient is φ = 16448832.

The previous prime is 20561033. The next prime is 20561053. The reversal of 20561045 is 54016502.

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 14455204 + 6105841 = 3802^2 + 2471^2 .

It is a cyclic number.

It is not a de Polignac number, because 20561045 - 2²⁰ = 19512469 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 20561045.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2056100 + ... + 2056109.

It is an arithmetic number, because the mean of its divisors is an integer number (6168315).

Almost surely, 2^20561045 is an apocalyptic number.

It is an amenable number.

20561045 is a deficient number, since it is larger than the sum of its proper divisors (4112215).

20561045 is an equidigital number, since it uses as much as digits as its factorization.

20561045 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4112214.

The product of its (nonzero) digits is 1200, while the sum is 23.

The square root of 20561045 is about 4534.4288504728. The cubic root of 20561045 is about 273.9565748930.

Adding to 20561045 its reverse (54016502), we get a palindrome (74577547).

The spelling of 20561045 in words is "twenty million, five hundred sixty-one thousand, forty-five".