1665106217 has 4 divisors (see below), whose sum is σ = 1670359236. Its totient is φ = 1659853200.

The previous prime is 1665106213. The next prime is 1665106277. The reversal of 1665106217 is 7126015661.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 7126015661 = 4657 ⋅1530173.

It can be written as a sum of positive squares in 2 ways, for example, as 69822736 + 1595283481 = 8356^2 + 39941^2 .

It is a cyclic number.

It is not a de Polignac number, because 1665106217 - 2² = 1665106213 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1665106213) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2626034 + ... + 2626667.

It is an arithmetic number, because the mean of its divisors is an integer number (417589809).

Almost surely, 2^1665106217 is an apocalyptic number.

It is an amenable number.

1665106217 is a deficient number, since it is larger than the sum of its proper divisors (5253019).

1665106217 is an equidigital number, since it uses as much as digits as its factorization.

1665106217 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5253018.

The product of its (nonzero) digits is 15120, while the sum is 35.

The square root of 1665106217 is about 40805.7130436413. The cubic root of 1665106217 is about 1185.2609624245.

The spelling of 1665106217 in words is "one billion, six hundred sixty-five million, one hundred six thousand, two hundred seventeen".