216311521 has 8 divisors (see below), whose sum is σ = 225379584. Its totient is φ = 207374160.

The previous prime is 216311489. The next prime is 216311533. The reversal of 216311521 is 125113612.

It is a happy number.

216311521 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 216311521 - 2⁵ = 216311489 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 216311492 and 216311501.

It is not an unprimeable number, because it can be changed into a prime (216311591) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 29290 + ... + 35923.

It is an arithmetic number, because the mean of its divisors is an integer number (28172448).

Almost surely, 2^216311521 is an apocalyptic number.

It is an amenable number.

216311521 is a deficient number, since it is larger than the sum of its proper divisors (9068063).

216311521 is a wasteful number, since it uses less digits than its factorization.

216311521 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 65351.

The product of its digits is 360, while the sum is 22.

The square root of 216311521 is about 14707.5327978557. The cubic root of 216311521 is about 600.2883068135.

The spelling of 216311521 in words is "two hundred sixteen million, three hundred eleven thousand, five hundred twenty-one".