18147640561 has 8 divisors (see below), whose sum is σ = 18776471400. Its totient is φ = 17519013120.

The previous prime is 18147640559. The next prime is 18147640583. The reversal of 18147640561 is 16504674181.

It can be written as a sum of positive squares in 4 ways, for example, as 5985962161 + 12161678400 = 77369^2 + 110280^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 18147640561 - 2¹ = 18147640559 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (18147640061) 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 in 7 ways as a sum of consecutive naturals, for example, 143305 + ... + 238393.

It is an arithmetic number, because the mean of its divisors is an integer number (2347058925).

Almost surely, 2^18147640561 is an apocalyptic number.

It is an amenable number.

18147640561 is a deficient number, since it is larger than the sum of its proper divisors (628830839).

18147640561 is an equidigital number, since it uses as much as digits as its factorization.

18147640561 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 101699.

The product of its (nonzero) digits is 161280, while the sum is 43.

The spelling of 18147640561 in words is "eighteen billion, one hundred forty-seven million, six hundred forty thousand, five hundred sixty-one".