1665505161 has 24 divisors (see below), whose sum is σ = 2480067720. Its totient is φ = 1076253696.

The previous prime is 1665505151. The next prime is 1665505201. The reversal of 1665505161 is 1615055661.

It can be written as a sum of positive squares in 4 ways, for example, as 250240761 + 1415264400 = 15819^2 + 37620^2 .

It is not a de Polignac number, because 1665505161 - 2⁹ = 1665504649 is a prime.

It is not an unprimeable number, because it can be changed into a prime (1665505151) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 80281 + ... + 98873.

It is an arithmetic number, because the mean of its divisors is an integer number (103336155).

Almost surely, 2^1665505161 is an apocalyptic number.

It is an amenable number.

1665505161 is a deficient number, since it is larger than the sum of its proper divisors (814562559).

1665505161 is a wasteful number, since it uses less digits than its factorization.

1665505161 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 18905 (or 18902 counting only the distinct ones).

The product of its (nonzero) digits is 27000, while the sum is 36.

The square root of 1665505161 is about 40810.6010859924. The cubic root of 1665505161 is about 1185.3556140421.

The spelling of 1665505161 in words is "one billion, six hundred sixty-five million, five hundred five thousand, one hundred sixty-one".