521165 has 4 divisors (see below), whose sum is σ = 625404. Its totient is φ = 416928.

The previous prime is 521161. The next prime is 521167. The reversal of 521165 is 561125.

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 292681 + 228484 = 541^2 + 478^2 .

It is a cyclic number.

It is not a de Polignac number, because 521165 - 2² = 521161 is a prime.

It is a super-2 number, since 2×521165² = 543225914450, which contains 22 as substring.

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (521161) 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, 52112 + ... + 52121.

It is an arithmetic number, because the mean of its divisors is an integer number (156351).

2⁵²¹¹⁶⁵ is an apocalyptic number.

It is an amenable number.

521165 is a deficient number, since it is larger than the sum of its proper divisors (104239).

521165 is a wasteful number, since it uses less digits than its factorization.

521165 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 104238.

The product of its digits is 300, while the sum is 20.

The square root of 521165 is about 721.9175853240. The cubic root of 521165 is about 80.4745235277.

It can be divided in two parts, 521 and 165, that added together give a palindrome (686).

The spelling of 521165 in words is "five hundred twenty-one thousand, one hundred sixty-five".