165661265 has 16 divisors (see below), whose sum is σ = 247847040. Its totient is φ = 103269120.

The previous prime is 165661259. The next prime is 165661267. The reversal of 165661265 is 562166561.

It is not a de Polignac number, because 165661265 - 2⁶ = 165661201 is a prime.

It is not an unprimeable number, because it can be changed into a prime (165661267) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 214760 + ... + 215529.

It is an arithmetic number, because the mean of its divisors is an integer number (15490440).

Almost surely, 2^165661265 is an apocalyptic number.

It is an amenable number.

165661265 is a deficient number, since it is larger than the sum of its proper divisors (82185775).

165661265 is a wasteful number, since it uses less digits than its factorization.

165661265 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 430312.

The product of its digits is 64800, while the sum is 38.

The square root of 165661265 is about 12870.9465463889. The cubic root of 165661265 is about 549.2123878118.

The spelling of 165661265 in words is "one hundred sixty-five million, six hundred sixty-one thousand, two hundred sixty-five".