216000661 has 2 divisors, whose sum is σ = 216000662. Its totient is φ = 216000660.

The previous prime is 216000643. The next prime is 216000677. The reversal of 216000661 is 166000612.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 215913636 + 87025 = 14694^2 + 295^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-216000661 is a prime.

It is a super-3 number, since 3×216000661³ (a number of 26 digits) contains 333 as substring.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (216000601) 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 as a sum of consecutive naturals, namely, 108000330 + 108000331.

It is an arithmetic number, because the mean of its divisors is an integer number (108000331).

Almost surely, 2^216000661 is an apocalyptic number.

It is an amenable number.

216000661 is a deficient number, since it is larger than the sum of its proper divisors (1).

216000661 is an equidigital number, since it uses as much as digits as its factorization.

216000661 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 432, while the sum is 22.

The square root of 216000661 is about 14696.9609443585. The cubic root of 216000661 is about 600.0006120364. Note that the first 3 decimals are identical.

The spelling of 216000661 in words is "two hundred sixteen million, six hundred sixty-one", and thus it is an aban number.