216563621 has 4 divisors (see below), whose sum is σ = 216600000. Its totient is φ = 216527244.

The previous prime is 216563587. The next prime is 216563623. The reversal of 216563621 is 126365612.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-216563621 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (216563623) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 6941 + ... + 21938.

It is an arithmetic number, because the mean of its divisors is an integer number (54150000).

Almost surely, 2^216563621 is an apocalyptic number.

It is an amenable number.

216563621 is a deficient number, since it is larger than the sum of its proper divisors (36379).

216563621 is an equidigital number, since it uses as much as digits as its factorization.

216563621 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 36378.

The product of its digits is 12960, while the sum is 32.

The square root of 216563621 is about 14716.1007403456. The cubic root of 216563621 is about 600.5214180371.

The spelling of 216563621 in words is "two hundred sixteen million, five hundred sixty-three thousand, six hundred twenty-one".