1565665165 has 4 divisors (see below), whose sum is σ = 1878798204. Its totient is φ = 1252532128.

The previous prime is 1565665147. The next prime is 1565665187. The reversal of 1565665165 is 5615665651.

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 389312361 + 1176352804 = 19731^2 + 34298^2 .

It is a cyclic number.

It is not a de Polignac number, because 1565665165 - 2¹⁷ = 1565534093 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, 156566512 + ... + 156566521.

It is an arithmetic number, because the mean of its divisors is an integer number (469699551).

Almost surely, 2^1565665165 is an apocalyptic number.

It is an amenable number.

1565665165 is a deficient number, since it is larger than the sum of its proper divisors (313133039).

1565665165 is an equidigital number, since it uses as much as digits as its factorization.

1565665165 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 313133038.

The product of its digits is 810000, while the sum is 46.

The square root of 1565665165 is about 39568.4870193441. The cubic root of 1565665165 is about 1161.1802209644.

The spelling of 1565665165 in words is "one billion, five hundred sixty-five million, six hundred sixty-five thousand, one hundred sixty-five".