20205461665 has 4 divisors (see below), whose sum is σ = 24246554004. Its totient is φ = 16164369328.

The previous prime is 20205461569. The next prime is 20205461677. The reversal of 20205461665 is 56616450202.

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 2762448481 + 17443013184 = 52559^2 + 132072^2 .

It is a cyclic number.

It is not a de Polignac number, because 20205461665 - 2²⁷ = 20071243937 is a prime.

It is a Duffinian number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2020546162 + ... + 2020546171.

It is an arithmetic number, because the mean of its divisors is an integer number (6061638501).

Almost surely, 2^20205461665 is an apocalyptic number.

It is an amenable number.

20205461665 is a deficient number, since it is larger than the sum of its proper divisors (4041092339).

20205461665 is an equidigital number, since it uses as much as digits as its factorization.

20205461665 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4041092338.

The product of its (nonzero) digits is 86400, while the sum is 37.

The spelling of 20205461665 in words is "twenty billion, two hundred five million, four hundred sixty-one thousand, six hundred sixty-five".