1666408165 has 8 divisors (see below), whose sum is σ = 1999987488. Its totient is φ = 1332928080.

The previous prime is 1666408151. The next prime is 1666408199. The reversal of 1666408165 is 5618046661.

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

It is not a de Polignac number, because 1666408165 - 2¹⁵ = 1666375397 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 7 ways as a sum of consecutive naturals, for example, 19254 + ... + 60856.

It is an arithmetic number, because the mean of its divisors is an integer number (249998436).

Almost surely, 2^1666408165 is an apocalyptic number.

It is an amenable number.

1666408165 is a deficient number, since it is larger than the sum of its proper divisors (333579323).

1666408165 is an equidigital number, since it uses as much as digits as its factorization.

1666408165 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 49619.

The product of its (nonzero) digits is 207360, while the sum is 43.

The square root of 1666408165 is about 40821.6629377099. The cubic root of 1666408165 is about 1185.5698008042.

The spelling of 1666408165 in words is "one billion, six hundred sixty-six million, four hundred eight thousand, one hundred sixty-five".