20365561 has 8 divisors (see below), whose sum is σ = 21218400. Its totient is φ = 19529760.

The previous prime is 20365559. The next prime is 20365567. The reversal of 20365561 is 16556302.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 20365561 - 2¹ = 20365559 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (20365567) 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 7 ways as a sum of consecutive naturals, for example, 1791 + ... + 6628.

It is an arithmetic number, because the mean of its divisors is an integer number (2652300).

Almost surely, 2^20365561 is an apocalyptic number.

It is an amenable number.

20365561 is a deficient number, since it is larger than the sum of its proper divisors (852839).

20365561 is an equidigital number, since it uses as much as digits as its factorization.

20365561 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 8519.

The product of its (nonzero) digits is 5400, while the sum is 28.

The square root of 20365561 is about 4512.8218444782. The cubic root of 20365561 is about 273.0855953115.

The spelling of 20365561 in words is "twenty million, three hundred sixty-five thousand, five hundred sixty-one".