18603718721 has 14 divisors (see below), whose sum is σ = 21704449410. Its totient is φ = 15945943776.

The previous prime is 18603718711. The next prime is 18603718723. The reversal of 18603718721 is 12781730681.

It can be written as a sum of positive squares in only one way, i.e., 14577181696 + 4026537025 = 120736^2 + 63455^2 .

It is a de Polignac number, because none of the positive numbers 2^k-18603718721 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (18603718723) by changing a digit.

It is a polite number, since it can be written in 13 ways as a sum of consecutive naturals, for example, 38585 + ... + 196713.

It is an arithmetic number, because the mean of its divisors is an integer number (1550317815).

Almost surely, 2^18603718721 is an apocalyptic number.

It is an amenable number.

18603718721 is a deficient number, since it is larger than the sum of its proper divisors (3100730689).

18603718721 is an frugal number, since it uses more digits than its factorization.

18603718721 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 158171 (or 158136 counting only the distinct ones).

The product of its (nonzero) digits is 112896, while the sum is 44.

The spelling of 18603718721 in words is "eighteen billion, six hundred three million, seven hundred eighteen thousand, seven hundred twenty-one".