521616 has 20 divisors (see below), whose sum is σ = 1347632. Its totient is φ = 173856.

The previous prime is 521603. The next prime is 521641. The reversal of 521616 is 616125.

It is a happy number.

It is an alternating number because its digits alternate between odd and even.

It is a junction number, because it is equal to n+sod(n) for n = 521592 and 521601.

It is an unprimeable number.

521616 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 3 ways as a sum of consecutive naturals, for example, 5386 + ... + 5481.

2⁵²¹⁶¹⁶ is an apocalyptic number.

It is an amenable number.

521616 is an abundant number, since it is smaller than the sum of its proper divisors (826016).

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

521616 is a wasteful number, since it uses less digits than its factorization.

521616 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10878 (or 10872 counting only the distinct ones).

The product of its digits is 360, while the sum is 21.

The square root of 521616 is about 722.2298803013. The cubic root of 521616 is about 80.4977302190.

The spelling of 521616 in words is "five hundred twenty-one thousand, six hundred sixteen".