216530521 has 8 divisors (see below), whose sum is σ = 218153088. Its totient is φ = 214914000.

The previous prime is 216530459. The next prime is 216530537. The reversal of 216530521 is 125035612.

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

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-216530521 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (216531521) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 89751 + ... + 92131.

It is an arithmetic number, because the mean of its divisors is an integer number (27269136).

Almost surely, 2^216530521 is an apocalyptic number.

It is an amenable number.

216530521 is a deficient number, since it is larger than the sum of its proper divisors (1622567).

216530521 is a wasteful number, since it uses less digits than its factorization.

216530521 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3023.

The product of its (nonzero) digits is 1800, while the sum is 25.

The square root of 216530521 is about 14714.9760788117. The cubic root of 216530521 is about 600.4908215290.

The spelling of 216530521 in words is "two hundred sixteen million, five hundred thirty thousand, five hundred twenty-one".