1218820508585 has 4 divisors (see below), whose sum is σ = 1462584610308. Its totient is φ = 975056406864.

The previous prime is 1218820508501. The next prime is 1218820508677. The reversal of 1218820508585 is 5858050288121.

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 327352189609 + 891468318976 = 572147^2 + 944176^2 .

It is a cyclic number.

It is not a de Polignac number, because 1218820508585 - 2¹⁰ = 1218820507561 is a prime.

It is a Duffinian number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 121882050854 + ... + 121882050863.

It is an arithmetic number, because the mean of its divisors is an integer number (365646152577).

Almost surely, 2^{1218820508585} is an apocalyptic number.

It is an amenable number.

1218820508585 is a deficient number, since it is larger than the sum of its proper divisors (243764101723).

1218820508585 is an equidigital number, since it uses as much as digits as its factorization.

1218820508585 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 243764101722.

The product of its (nonzero) digits is 2048000, while the sum is 53.

The spelling of 1218820508585 in words is "one trillion, two hundred eighteen billion, eight hundred twenty million, five hundred eight thousand, five hundred eighty-five".