1155566565 has 24 divisors (see below), whose sum is σ = 2003916408. Its totient is φ = 616014720.

The previous prime is 1155566557. The next prime is 1155566593. The reversal of 1155566565 is 5656655511.

It can be written as a sum of positive squares in 4 ways, for example, as 286083396 + 869483169 = 16914^2 + 29487^2 .

It is not a de Polignac number, because 1155566565 - 2³ = 1155566557 is a prime.

It is a super-2 number, since 2×1155566565² = 2670668172291798450, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (45).

It is a Curzon number.

It is a self number, because there is not a number n which added to its sum of digits gives 1155566565.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 121275 + ... + 130455.

It is an arithmetic number, because the mean of its divisors is an integer number (83496517).

Almost surely, 2^1155566565 is an apocalyptic number.

1155566565 is a gapful number since it is divisible by the number (15) formed by its first and last digit.

It is an amenable number.

1155566565 is a deficient number, since it is larger than the sum of its proper divisors (848349843).

1155566565 is a wasteful number, since it uses less digits than its factorization.

1155566565 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 11989 (or 11986 counting only the distinct ones).

The product of its digits is 675000, while the sum is 45.

The square root of 1155566565 is about 33993.6253582933. The cubic root of 1155566565 is about 1049.3772770135.

The spelling of 1155566565 in words is "one billion, one hundred fifty-five million, five hundred sixty-six thousand, five hundred sixty-five".