165665251 has 8 divisors (see below), whose sum is σ = 175237920. Its totient is φ = 156290112.

The previous prime is 165665249. The next prime is 165665267. The reversal of 165665251 is 152566561.

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

It is a cyclic number.

It is not a de Polignac number, because 165665251 - 2¹ = 165665249 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 165665251.

It is not an unprimeable number, because it can be changed into a prime (165665551) 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 7 ways as a sum of consecutive naturals, for example, 47656 + ... + 51013.

It is an arithmetic number, because the mean of its divisors is an integer number (21904740).

Almost surely, 2^165665251 is an apocalyptic number.

165665251 is a deficient number, since it is larger than the sum of its proper divisors (9572669).

165665251 is an equidigital number, since it uses as much as digits as its factorization.

165665251 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 98765.

The product of its digits is 54000, while the sum is 37.

The square root of 165665251 is about 12871.1013903240. The cubic root of 165665251 is about 549.2167926697.

The spelling of 165665251 in words is "one hundred sixty-five million, six hundred sixty-five thousand, two hundred fifty-one".