18786661 has 2 divisors, whose sum is σ = 18786662. Its totient is φ = 18786660.

The previous prime is 18786643. The next prime is 18786679. The reversal of 18786661 is 16668781.

It is a balanced prime because it is at equal distance from previous prime (18786643) and next prime (18786679).

It can be written as a sum of positive squares in only one way, i.e., 18541636 + 245025 = 4306^2 + 495^2 .

It is a cyclic number.

It is not a de Polignac number, because 18786661 - 2¹¹ = 18784613 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (18786601) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9393330 + 9393331.

It is an arithmetic number, because the mean of its divisors is an integer number (9393331).

Almost surely, 2^18786661 is an apocalyptic number.

It is an amenable number.

18786661 is a deficient number, since it is larger than the sum of its proper divisors (1).

18786661 is an equidigital number, since it uses as much as digits as its factorization.

18786661 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 96768, while the sum is 43.

The square root of 18786661 is about 4334.3581993186. The cubic root of 18786661 is about 265.8376767950.

The spelling of 18786661 in words is "eighteen million, seven hundred eighty-six thousand, six hundred sixty-one".