665645565 has 16 divisors (see below), whose sum is σ = 1146958848. Its totient is φ = 327702336.

The previous prime is 665645551. The next prime is 665645569. The reversal of 665645565 is 565546566.

It is not a de Polignac number, because 665645565 - 2⁴ = 665645549 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (665645569) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 1706589 + ... + 1706978.

It is an arithmetic number, because the mean of its divisors is an integer number (71684928).

Almost surely, 2^665645565 is an apocalyptic number.

665645565 is a gapful number since it is divisible by the number (65) formed by its first and last digit.

It is an amenable number.

665645565 is a deficient number, since it is larger than the sum of its proper divisors (481313283).

665645565 is a wasteful number, since it uses less digits than its factorization.

665645565 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3413588.

The product of its digits is 3240000, while the sum is 48.

The square root of 665645565 is about 25800.1078486118. The cubic root of 665645565 is about 873.1342295987.

The spelling of 665645565 in words is "six hundred sixty-five million, six hundred forty-five thousand, five hundred sixty-five".