1609696665 has 64 divisors (see below), whose sum is σ = 2903155200. Its totient is φ = 846173952.

The previous prime is 1609696637. The next prime is 1609696681. The reversal of 1609696665 is 5666969061.

It is a happy number.

It is not a de Polignac number, because 1609696665 - 2⁵ = 1609696633 is a prime.

It is a super-2 number, since 2×1609696665² = 5182246706624244450, which contains 22 as substring.

It is a Smith number, since the sum of its digits (54) coincides with the sum of the digits of its prime factors.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 3666516 + ... + 3666954.

It is an arithmetic number, because the mean of its divisors is an integer number (45361800).

Almost surely, 2^1609696665 is an apocalyptic number.

1609696665 is a gapful number since it is divisible by the number (15) formed by its first and last digit.

It is an amenable number.

1609696665 is a deficient number, since it is larger than the sum of its proper divisors (1293458535).

1609696665 is a wasteful number, since it uses less digits than its factorization.

1609696665 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 783 (or 777 counting only the distinct ones).

The product of its (nonzero) digits is 3149280, while the sum is 54.

The square root of 1609696665 is about 40121.0252236904. The cubic root of 1609696665 is about 1171.9651065434.

It can be divided in two parts, 1609696 and 665, that added together give a square (1610361 = 1269²).

The spelling of 1609696665 in words is "one billion, six hundred nine million, six hundred ninety-six thousand, six hundred sixty-five".