216541305 has 24 divisors (see below), whose sum is σ = 382424328. Its totient is φ = 113308416.

The previous prime is 216541301. The next prime is 216541307. The reversal of 216541305 is 503145612.

216541305 is a `hidden beast` number, since 2 + 1 + 654 + 1 + 3 + 0 + 5 = 666.

It can be written as a sum of positive squares in 4 ways, for example, as 2913849 + 213627456 = 1707^2 + 14616^2 .

It is not a de Polignac number, because 216541305 - 2² = 216541301 is a prime.

It is a super-2 number, since 2×216541305² = 93780273542206050, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (216541301) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 43012 + ... + 47781.

It is an arithmetic number, because the mean of its divisors is an integer number (15934347).

Almost surely, 2^216541305 is an apocalyptic number.

It is an amenable number.

216541305 is a deficient number, since it is larger than the sum of its proper divisors (165883023).

216541305 is a wasteful number, since it uses less digits than its factorization.

216541305 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 90857 (or 90854 counting only the distinct ones).

The product of its (nonzero) digits is 3600, while the sum is 27.

The square root of 216541305 is about 14715.3425036592. The cubic root of 216541305 is about 600.5007902323.

Adding to 216541305 its reverse (503145612), we get a palindrome (719686917).

The spelling of 216541305 in words is "two hundred sixteen million, five hundred forty-one thousand, three hundred five".