161665759 has 4 divisors (see below), whose sum is σ = 165105504. Its totient is φ = 158226016.

The previous prime is 161665711. The next prime is 161665783. The reversal of 161665759 is 957566161.

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

It is a cyclic number.

It is not a de Polignac number, because 161665759 - 2¹⁷ = 161534687 is a prime.

It is a super-2 number, since 2×161665759² = 52271635266092162, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (161665789) 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, 1719802 + ... + 1719895.

It is an arithmetic number, because the mean of its divisors is an integer number (41276376).

Almost surely, 2^161665759 is an apocalyptic number.

161665759 is a deficient number, since it is larger than the sum of its proper divisors (3439745).

161665759 is an equidigital number, since it uses as much as digits as its factorization.

161665759 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3439744.

The product of its digits is 340200, while the sum is 46.

The square root of 161665759 is about 12714.7850552025. The cubic root of 161665759 is about 544.7610084756.

The spelling of 161665759 in words is "one hundred sixty-one million, six hundred sixty-five thousand, seven hundred fifty-nine".