20355565 has 8 divisors (see below), whose sum is σ = 24473880. Its totient is φ = 16252992.

The previous prime is 20355563. The next prime is 20355571. The reversal of 20355565 is 56555302.

It can be written as a sum of positive squares in 4 ways, for example, as 51529 + 20304036 = 227^2 + 4506^2 .

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 20355565 - 2¹ = 20355563 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20355563) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 870 + ... + 6439.

It is an arithmetic number, because the mean of its divisors is an integer number (3059235).

Almost surely, 2^20355565 is an apocalyptic number.

It is an amenable number.

20355565 is a deficient number, since it is larger than the sum of its proper divisors (4118315).

20355565 is an equidigital number, since it uses as much as digits as its factorization.

20355565 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7871.

The product of its (nonzero) digits is 22500, while the sum is 31.

The square root of 20355565 is about 4511.7141975085. The cubic root of 20355565 is about 273.0409085918.

The spelling of 20355565 in words is "twenty million, three hundred fifty-five thousand, five hundred sixty-five".