165257905 has 4 divisors (see below), whose sum is σ = 198309492. Its totient is φ = 132206320.

The previous prime is 165257903. The next prime is 165257927. The reversal of 165257905 is 509752561.

165257905 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

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

It can be written as a sum of positive squares in 2 ways, for example, as 75064896 + 90193009 = 8664^2 + 9497^2 .

It is not a de Polignac number, because 165257905 - 2¹ = 165257903 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (165257903) 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, 16525786 + ... + 16525795.

It is an arithmetic number, because the mean of its divisors is an integer number (49577373).

Almost surely, 2^165257905 is an apocalyptic number.

It is an amenable number.

165257905 is a deficient number, since it is larger than the sum of its proper divisors (33051587).

165257905 is an equidigital number, since it uses as much as digits as its factorization.

165257905 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 33051586.

The product of its (nonzero) digits is 94500, while the sum is 40.

The square root of 165257905 is about 12855.2675973703. The cubic root of 165257905 is about 548.7662759825.

The spelling of 165257905 in words is "one hundred sixty-five million, two hundred fifty-seven thousand, nine hundred five".