20965165565 has 4 divisors (see below), whose sum is σ = 25158198684. Its totient is φ = 16772132448.

The previous prime is 20965165549. The next prime is 20965165567. The reversal of 20965165565 is 56556156902.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 13885794244 + 7079371321 = 117838^2 + 84139^2 .

It is a cyclic number.

It is not a de Polignac number, because 20965165565 - 2⁴ = 20965165549 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20965165567) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2096516552 + ... + 2096516561.

It is an arithmetic number, because the mean of its divisors is an integer number (6289549671).

Almost surely, 2^20965165565 is an apocalyptic number.

It is an amenable number.

20965165565 is a deficient number, since it is larger than the sum of its proper divisors (4193033119).

20965165565 is an equidigital number, since it uses as much as digits as its factorization.

20965165565 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4193033118.

The product of its (nonzero) digits is 2430000, while the sum is 50.

The spelling of 20965165565 in words is "twenty billion, nine hundred sixty-five million, one hundred sixty-five thousand, five hundred sixty-five".