216909533 has 2 divisors, whose sum is σ = 216909534. Its totient is φ = 216909532.

The previous prime is 216909467. The next prime is 216909569. The reversal of 216909533 is 335909612.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 179479609 + 37429924 = 13397^2 + 6118^2 .

It is a cyclic number.

It is not a de Polignac number, because 216909533 - 2²² = 212715229 is a prime.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (216909233) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 108454766 + 108454767.

It is an arithmetic number, because the mean of its divisors is an integer number (108454767).

Almost surely, 2^216909533 is an apocalyptic number.

It is an amenable number.

216909533 is a deficient number, since it is larger than the sum of its proper divisors (1).

216909533 is an equidigital number, since it uses as much as digits as its factorization.

216909533 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 43740, while the sum is 38.

The square root of 216909533 is about 14727.8488924894. The cubic root of 216909533 is about 600.8409808864.

The spelling of 216909533 in words is "two hundred sixteen million, nine hundred nine thousand, five hundred thirty-three".