20505284465 has 8 divisors (see below), whose sum is σ = 24661146600. Its totient is φ = 16367690752.

The previous prime is 20505284453. The next prime is 20505284479. The reversal of 20505284465 is 56448250502.

It can be written as a sum of positive squares in 4 ways, for example, as 6273748849 + 14231535616 = 79207^2 + 119296^2 .

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 20505284465 - 2⁸ = 20505284209 is a prime.

It is a Curzon number.

It is an unprimeable number.

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 7 ways as a sum of consecutive naturals, for example, 4564634 + ... + 4569123.

It is an arithmetic number, because the mean of its divisors is an integer number (3082643325).

Almost surely, 2^20505284465 is an apocalyptic number.

It is an amenable number.

20505284465 is a deficient number, since it is larger than the sum of its proper divisors (4155862135).

20505284465 is an equidigital number, since it uses as much as digits as its factorization.

20505284465 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9134211.

The product of its (nonzero) digits is 384000, while the sum is 41.

The spelling of 20505284465 in words is "twenty billion, five hundred five million, two hundred eighty-four thousand, four hundred sixty-five".