18628661729 has 4 divisors (see below), whose sum is σ = 18628987284. Its totient is φ = 18628336176.

The previous prime is 18628661719. The next prime is 18628661749. The reversal of 18628661729 is 92716682681.

It is a happy number.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 2289431104 + 16339230625 = 47848^2 + 127825^2 .

It is a cyclic number.

It is not a de Polignac number, because 18628661729 - 2²⁸ = 18360226273 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (18628661719) 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 3 ways as a sum of consecutive naturals, for example, 51662 + ... + 199815.

It is an arithmetic number, because the mean of its divisors is an integer number (4657246821).

Almost surely, 2^18628661729 is an apocalyptic number.

It is an amenable number.

18628661729 is a deficient number, since it is larger than the sum of its proper divisors (325555).

18628661729 is an equidigital number, since it uses as much as digits as its factorization.

18628661729 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 325554.

The product of its digits is 3483648, while the sum is 56.

The spelling of 18628661729 in words is "eighteen billion, six hundred twenty-eight million, six hundred sixty-one thousand, seven hundred twenty-nine".