20655565 has 32 divisors (see below), whose sum is σ = 30240000. Its totient is φ = 13229568.

The previous prime is 20655563. The next prime is 20655619. The reversal of 20655565 is 56555602.

It is a happy number.

It is a cyclic number.

It is not a de Polignac number, because 20655565 - 2¹ = 20655563 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 20655565.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20655563) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 59011 + ... + 59359.

It is an arithmetic number, because the mean of its divisors is an integer number (945000).

Almost surely, 2^20655565 is an apocalyptic number.

It is an amenable number.

20655565 is a deficient number, since it is larger than the sum of its proper divisors (9584435).

20655565 is a wasteful number, since it uses less digits than its factorization.

20655565 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 469.

The product of its (nonzero) digits is 45000, while the sum is 34.

The square root of 20655565 is about 4544.8393811003. The cubic root of 20655565 is about 274.3757299393.

The spelling of 20655565 in words is "twenty million, six hundred fifty-five thousand, five hundred sixty-five".