1665161635 has 4 divisors (see below), whose sum is σ = 1998193968. Its totient is φ = 1332129304.

The previous prime is 1665161633. The next prime is 1665161639. The reversal of 1665161635 is 5361615661.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 5361615661 = 167 ⋅32105483.

It is a cyclic number.

It is not a de Polignac number, because 1665161635 - 2¹ = 1665161633 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1665161633) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 166516159 + ... + 166516168.

It is an arithmetic number, because the mean of its divisors is an integer number (499548492).

Almost surely, 2^1665161635 is an apocalyptic number.

1665161635 is a deficient number, since it is larger than the sum of its proper divisors (333032333).

1665161635 is an equidigital number, since it uses as much as digits as its factorization.

1665161635 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 333032332.

The product of its digits is 97200, while the sum is 40.

The square root of 1665161635 is about 40806.3920850643. The cubic root of 1665161635 is about 1185.2741115483.

The spelling of 1665161635 in words is "one billion, six hundred sixty-five million, one hundred sixty-one thousand, six hundred thirty-five".