18720555505 has 16 divisors (see below), whose sum is σ = 23708805120. Its totient is φ = 14151138048.

The previous prime is 18720555487. The next prime is 18720555547. The reversal of 18720555505 is 50555502781.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-18720555505 is a prime.

It is an unprimeable number.

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 15 ways as a sum of consecutive naturals, for example, 220872 + ... + 293641.

It is an arithmetic number, because the mean of its divisors is an integer number (1481800320).

Almost surely, 2^18720555505 is an apocalyptic number.

It is an amenable number.

18720555505 is a deficient number, since it is larger than the sum of its proper divisors (4988249615).

18720555505 is a wasteful number, since it uses less digits than its factorization.

18720555505 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 514920.

The product of its (nonzero) digits is 350000, while the sum is 43.

The spelling of 18720555505 in words is "eighteen billion, seven hundred twenty million, five hundred fifty-five thousand, five hundred five".