165661039 has 4 divisors (see below), whose sum is σ = 175405824. Its totient is φ = 155916256.

The previous prime is 165661009. The next prime is 165661049. The reversal of 165661039 is 930166561.

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 165661039 - 2⁹ = 165660527 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 165660989 and 165661007.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (165661009) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 4872367 + ... + 4872400.

It is an arithmetic number, because the mean of its divisors is an integer number (43851456).

Almost surely, 2^165661039 is an apocalyptic number.

165661039 is a deficient number, since it is larger than the sum of its proper divisors (9744785).

165661039 is an equidigital number, since it uses as much as digits as its factorization.

165661039 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9744784.

The product of its (nonzero) digits is 29160, while the sum is 37.

The square root of 165661039 is about 12870.9377669228. The cubic root of 165661039 is about 549.2121380611.

The spelling of 165661039 in words is "one hundred sixty-five million, six hundred sixty-one thousand, thirty-nine".