18666761 has 2 divisors, whose sum is σ = 18666762. Its totient is φ = 18666760.

The previous prime is 18666733. The next prime is 18666763. The reversal of 18666761 is 16766681.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 13097161 + 5569600 = 3619^2 + 2360^2 .

It is an emirp because it is prime and its reverse (16766681) is a distict prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-18666761 is a prime.

It is a super-2 number, since 2×18666761² = 696895932462242, which contains 22 as substring.

Together with 18666763, it forms a pair of twin primes.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (18666763) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9333380 + 9333381.

It is an arithmetic number, because the mean of its divisors is an integer number (9333381).

Almost surely, 2^18666761 is an apocalyptic number.

It is an amenable number.

18666761 is a deficient number, since it is larger than the sum of its proper divisors (1).

18666761 is an equidigital number, since it uses as much as digits as its factorization.

18666761 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 72576, while the sum is 41.

The square root of 18666761 is about 4320.5047158868. The cubic root of 18666761 is about 265.2709273801.

The spelling of 18666761 in words is "eighteen million, six hundred sixty-six thousand, seven hundred sixty-one".