155665 has 8 divisors (see below), whose sum is σ = 188928. Its totient is φ = 123120.

The previous prime is 155663. The next prime is 155671. The reversal of 155665 is 566551.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 155665 - 2¹ = 155663 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (155663) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (5) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 720 + ... + 910.

It is an arithmetic number, because the mean of its divisors is an integer number (23616).

2¹⁵⁵⁶⁶⁵ is an apocalyptic number.

It is an amenable number.

155665 is a deficient number, since it is larger than the sum of its proper divisors (33263).

155665 is a wasteful number, since it uses less digits than its factorization.

155665 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 359.

The product of its digits is 4500, while the sum is 28.

The square root of 155665 is about 394.5440406342. The cubic root of 155665 is about 53.7935648250.

It can be divided in two parts, 155 and 665, that added together give a triangular number (820 = T₄₀).

The spelling of 155665 in words is "one hundred fifty-five thousand, six hundred sixty-five".