1645585665 has 16 divisors (see below), whose sum is σ = 2656240128. Its totient is φ = 869878016.

The previous prime is 1645585663. The next prime is 1645585681. The reversal of 1645585665 is 5665855461.

It is a cyclic number.

It is not a de Polignac number, because 1645585665 - 2¹ = 1645585663 is a prime.

It is not an unprimeable number, because it can be changed into a prime (1645585661) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 483729 + ... + 487118.

It is an arithmetic number, because the mean of its divisors is an integer number (166015008).

Almost surely, 2^1645585665 is an apocalyptic number.

1645585665 is a gapful number since it is divisible by the number (15) formed by its first and last digit.

It is an amenable number.

1645585665 is a deficient number, since it is larger than the sum of its proper divisors (1010654463).

1645585665 is a wasteful number, since it uses less digits than its factorization.

1645585665 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 970968.

The product of its digits is 4320000, while the sum is 51.

The square root of 1645585665 is about 40565.8189243111. The cubic root of 1645585665 is about 1180.6110177006.

The spelling of 1645585665 in words is "one billion, six hundred forty-five million, five hundred eighty-five thousand, six hundred sixty-five".