1665005671 has 8 divisors (see below), whose sum is σ = 1903518080. Its totient is φ = 1426656888.

The previous prime is 1665005633. The next prime is 1665005731. The reversal of 1665005671 is 1765005661.

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

It is a cyclic number.

It is not a de Polignac number, because 1665005671 - 2¹⁹ = 1664481383 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 1665005671.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1665005611) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 18261 + ... + 60526.

It is an arithmetic number, because the mean of its divisors is an integer number (237939760).

Almost surely, 2^1665005671 is an apocalyptic number.

1665005671 is a deficient number, since it is larger than the sum of its proper divisors (238512409).

1665005671 is an equidigital number, since it uses as much as digits as its factorization.

1665005671 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 81813.

The product of its (nonzero) digits is 37800, while the sum is 37.

The square root of 1665005671 is about 40804.4810161825. The cubic root of 1665005671 is about 1185.2371049580.

The spelling of 1665005671 in words is "one billion, six hundred sixty-five million, five thousand, six hundred seventy-one".