521365 has 12 divisors (see below), whose sum is σ = 678564. Its totient is φ = 384384.

The previous prime is 521363. The next prime is 521369. The reversal of 521365 is 563125.

It is a happy number.

It can be written as a sum of positive squares in 6 ways, for example, as 252004 + 269361 = 502^2 + 519^2 .

It is not a de Polignac number, because 521365 - 2¹ = 521363 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (521363) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 537 + ... + 1153.

It is an arithmetic number, because the mean of its divisors is an integer number (56547).

2⁵²¹³⁶⁵ is an apocalyptic number.

It is an amenable number.

521365 is a deficient number, since it is larger than the sum of its proper divisors (157199).

521365 is a wasteful number, since it uses less digits than its factorization.

521365 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 648 (or 635 counting only the distinct ones).

The product of its digits is 900, while the sum is 22.

The square root of 521365 is about 722.0560920039. The cubic root of 521365 is about 80.4848163948.

The spelling of 521365 in words is "five hundred twenty-one thousand, three hundred sixty-five".