1218882565 has 4 divisors (see below), whose sum is σ = 1462659084. Its totient is φ = 975106048.

The previous prime is 1218882551. The next prime is 1218882569. The reversal of 1218882565 is 5652888121.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 5652888121 = 19013 ⋅297317.

It can be written as a sum of positive squares in 2 ways, for example, as 679853476 + 539029089 = 26074^2 + 23217^2 .

It is a cyclic number.

It is not a de Polignac number, because 1218882565 - 2⁷ = 1218882437 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1218882569) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 121888252 + ... + 121888261.

It is an arithmetic number, because the mean of its divisors is an integer number (365664771).

Almost surely, 2^1218882565 is an apocalyptic number.

It is an amenable number.

1218882565 is a deficient number, since it is larger than the sum of its proper divisors (243776519).

1218882565 is an equidigital number, since it uses as much as digits as its factorization.

1218882565 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 243776518.

The product of its digits is 307200, while the sum is 46.

The square root of 1218882565 is about 34912.4986931615. The cubic root of 1218882565 is about 1068.2033975673.

The spelling of 1218882565 in words is "one billion, two hundred eighteen million, eight hundred eighty-two thousand, five hundred sixty-five".