18601500661 has 2 divisors, whose sum is σ = 18601500662. Its totient is φ = 18601500660.

The previous prime is 18601500641. The next prime is 18601500667. The reversal of 18601500661 is 16600510681.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 15608754225 + 2992746436 = 124935^2 + 54706^2 .

It is a cyclic number.

It is not a de Polignac number, because 18601500661 - 2⁹ = 18601500149 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (18601500667) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9300750330 + 9300750331.

It is an arithmetic number, because the mean of its divisors is an integer number (9300750331).

Almost surely, 2^18601500661 is an apocalyptic number.

It is an amenable number.

18601500661 is a deficient number, since it is larger than the sum of its proper divisors (1).

18601500661 is an equidigital number, since it uses as much as digits as its factorization.

18601500661 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 8640, while the sum is 34.

The spelling of 18601500661 in words is "eighteen billion, six hundred one million, five hundred thousand, six hundred sixty-one".