18351666661 has 2 divisors, whose sum is σ = 18351666662. Its totient is φ = 18351666660.

The previous prime is 18351666653. The next prime is 18351666679. The reversal of 18351666661 is 16666615381.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 13620290436 + 4731376225 = 116706^2 + 68785^2 .

It is a cyclic number.

It is not a de Polignac number, because 18351666661 - 2³ = 18351666653 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (18351666601) 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, 9175833330 + 9175833331.

It is an arithmetic number, because the mean of its divisors is an integer number (9175833331).

Almost surely, 2^18351666661 is an apocalyptic number.

It is an amenable number.

18351666661 is a deficient number, since it is larger than the sum of its proper divisors (1).

18351666661 is an equidigital number, since it uses as much as digits as its factorization.

18351666661 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 933120, while the sum is 49.

The spelling of 18351666661 in words is "eighteen billion, three hundred fifty-one million, six hundred sixty-six thousand, six hundred sixty-one".