20530555665 has 48 divisors (see below), whose sum is σ = 36412184448. Its totient is φ = 9857419264.

The previous prime is 20530555663. The next prime is 20530555667. The reversal of 20530555665 is 56655503502.

It is an interprime number because it is at equal distance from previous prime (20530555663) and next prime (20530555667).

It is not a de Polignac number, because 20530555665 - 2¹ = 20530555663 is a prime.

It is not an unprimeable number, because it can be changed into a prime (20530555663) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 3252 + ... + 202661.

It is an arithmetic number, because the mean of its divisors is an integer number (758587176).

Almost surely, 2^20530555665 is an apocalyptic number.

It is an amenable number.

20530555665 is a deficient number, since it is larger than the sum of its proper divisors (15881628783).

20530555665 is a wasteful number, since it uses less digits than its factorization.

20530555665 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 205978 (or 205961 counting only the distinct ones).

The product of its (nonzero) digits is 675000, while the sum is 42.

The spelling of 20530555665 in words is "twenty billion, five hundred thirty million, five hundred fifty-five thousand, six hundred sixty-five".