1155216565 has 4 divisors (see below), whose sum is σ = 1386259884. Its totient is φ = 924173248.

The previous prime is 1155216551. The next prime is 1155216577. The reversal of 1155216565 is 5656125511.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 5656125511 = 5737 ⋅985903.

It can be written as a sum of positive squares in 2 ways, for example, as 780755364 + 374461201 = 27942^2 + 19351^2 .

It is a cyclic number.

It is not a de Polignac number, because 1155216565 - 2⁹ = 1155216053 is a prime.

It is a Duffinian number.

It is a congruent 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, 115521652 + ... + 115521661.

It is an arithmetic number, because the mean of its divisors is an integer number (346564971).

Almost surely, 2^1155216565 is an apocalyptic number.

It is an amenable number.

1155216565 is a deficient number, since it is larger than the sum of its proper divisors (231043319).

1155216565 is an equidigital number, since it uses as much as digits as its factorization.

1155216565 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 231043318.

The product of its digits is 45000, while the sum is 37.

The square root of 1155216565 is about 33988.4769443998. The cubic root of 1155216565 is about 1049.2713205804.

The spelling of 1155216565 in words is "one billion, one hundred fifty-five million, two hundred sixteen thousand, five hundred sixty-five".