218797561 has 2 divisors, whose sum is σ = 218797562. Its totient is φ = 218797560.

The previous prime is 218797543. The next prime is 218797577. The reversal of 218797561 is 165797812.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 207907561 + 10890000 = 14419^2 + 3300^2 .

It is a cyclic number.

It is not a de Polignac number, because 218797561 - 2⁵ = 218797529 is a prime.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (218797261) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 109398780 + 109398781.

It is an arithmetic number, because the mean of its divisors is an integer number (109398781).

Almost surely, 2^218797561 is an apocalyptic number.

It is an amenable number.

218797561 is a deficient number, since it is larger than the sum of its proper divisors (1).

218797561 is an equidigital number, since it uses as much as digits as its factorization.

218797561 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 211680, while the sum is 46.

The square root of 218797561 is about 14791.8072256232. The cubic root of 218797561 is about 602.5792309846.

The spelling of 218797561 in words is "two hundred eighteen million, seven hundred ninety-seven thousand, five hundred sixty-one".