216521203 has 2 divisors, whose sum is σ = 216521204. Its totient is φ = 216521202.

The previous prime is 216521177. The next prime is 216521219. The reversal of 216521203 is 302125612.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 216521203 - 2⁵ = 216521171 is a prime.

It is not a weakly prime, because it can be changed into another prime (216521233) 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 as a sum of consecutive naturals, namely, 108260601 + 108260602.

It is an arithmetic number, because the mean of its divisors is an integer number (108260602).

Almost surely, 2^216521203 is an apocalyptic number.

216521203 is a deficient number, since it is larger than the sum of its proper divisors (1).

216521203 is an equidigital number, since it uses as much as digits as its factorization.

216521203 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 720, while the sum is 22.

The square root of 216521203 is about 14714.6594591924. The cubic root of 216521203 is about 600.4822077261.

Adding to 216521203 its reverse (302125612), we get a palindrome (518646815).

The spelling of 216521203 in words is "two hundred sixteen million, five hundred twenty-one thousand, two hundred three".