1664405565 has 8 divisors (see below), whose sum is σ = 2663048928. Its totient is φ = 887682960.

The previous prime is 1664405539. The next prime is 1664405569. The reversal of 1664405565 is 5655044661.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 1664405565 - 2¹² = 1664401469 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1664405569) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 55480171 + ... + 55480200.

It is an arithmetic number, because the mean of its divisors is an integer number (332881116).

Almost surely, 2^1664405565 is an apocalyptic number.

1664405565 is a gapful number since it is divisible by the number (15) formed by its first and last digit.

It is an amenable number.

1664405565 is a deficient number, since it is larger than the sum of its proper divisors (998643363).

1664405565 is a wasteful number, since it uses less digits than its factorization.

1664405565 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 110960379.

The product of its (nonzero) digits is 432000, while the sum is 42.

The square root of 1664405565 is about 40797.1269208997. The cubic root of 1664405565 is about 1185.0946923565.

The spelling of 1664405565 in words is "one billion, six hundred sixty-four million, four hundred five thousand, five hundred sixty-five".