218886738661 has 2 divisors, whose sum is σ = 218886738662. Its totient is φ = 218886738660.

The previous prime is 218886738659. The next prime is 218886738671. The reversal of 218886738661 is 166837688812.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 168567724900 + 50319013761 = 410570^2 + 224319^2 .

It is a cyclic number.

It is not a de Polignac number, because 218886738661 - 2¹ = 218886738659 is a prime.

It is a super-2 number, since 2×218886738661² (a number of 23 digits) contains 22 as substring.

Together with 218886738659, it forms a pair of twin primes.

It is a junction number, because it is equal to n+sod(n) for n = 218886738593 and 218886738602.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (218886738671) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 109443369330 + 109443369331.

It is an arithmetic number, because the mean of its divisors is an integer number (109443369331).

Almost surely, 2^218886738661 is an apocalyptic number.

It is an amenable number.

218886738661 is a deficient number, since it is larger than the sum of its proper divisors (1).

218886738661 is an equidigital number, since it uses as much as digits as its factorization.

218886738661 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 37158912, while the sum is 64.

The spelling of 218886738661 in words is "two hundred eighteen billion, eight hundred eighty-six million, seven hundred thirty-eight thousand, six hundred sixty-one".