521316 has 30 divisors (see below), whose sum is σ = 1363670. Its totient is φ = 173664.

The previous prime is 521309. The next prime is 521317. The reversal of 521316 is 613125.

It can be written as a sum of positive squares in only one way, i.e., 518400 + 2916 = 720^2 + 54^2 .

It is a Harshad number since it is a multiple of its sum of digits (18).

It is a nialpdrome in base 9.

It is not an unprimeable number, because it can be changed into a prime (521317) by changing a digit.

521316 is an untouchable number, because it is not equal to the sum of proper divisors of any number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 9 ways as a sum of consecutive naturals, for example, 481 + ... + 1128.

2⁵²¹³¹⁶ is an apocalyptic number.

It is an amenable number.

521316 is an abundant number, since it is smaller than the sum of its proper divisors (842354).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

521316 is a wasteful number, since it uses less digits than its factorization.

521316 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1625 (or 1614 counting only the distinct ones).

The product of its digits is 180, while the sum is 18.

The square root of 521316 is about 722.0221603247. The cubic root of 521316 is about 80.4822948859.

Subtracting 521316 from its reverse (613125), we obtain a square (91809 = 303²).

It can be divided in two parts, 5 and 21316, that added together give a triangular number (21321 = T₂₀₆).

The spelling of 521316 in words is "five hundred twenty-one thousand, three hundred sixteen".