1009865565 has 24 divisors (see below), whose sum is σ = 1771529760. Its totient is φ = 532103904.

The previous prime is 1009865557. The next prime is 1009865567. The reversal of 1009865565 is 5655689001.

It is a happy number.

1009865565 is a `hidden beast` number, since 1 + 0 + 0 + 9 + 86 + 5 + 565 = 666.

It is not a de Polignac number, because 1009865565 - 2³ = 1009865557 is a prime.

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

It is a self number, because there is not a number n which added to its sum of digits gives 1009865565.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1009865567) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 131455 + ... + 138924.

It is an arithmetic number, because the mean of its divisors is an integer number (73813740).

Almost surely, 2^1009865565 is an apocalyptic number.

1009865565 is a gapful number since it is divisible by the number (15) formed by its first and last digit.

It is an amenable number.

1009865565 is a deficient number, since it is larger than the sum of its proper divisors (761664195).

1009865565 is a wasteful number, since it uses less digits than its factorization.

1009865565 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 270473 (or 270470 counting only the distinct ones).

The product of its (nonzero) digits is 324000, while the sum is 45.

The square root of 1009865565 is about 31778.3820387382. The cubic root of 1009865565 is about 1003.2777661771.

The spelling of 1009865565 in words is "one billion, nine million, eight hundred sixty-five thousand, five hundred sixty-five".