1666052209 has 4 divisors (see below), whose sum is σ = 1688874916. Its totient is φ = 1643229504.

The previous prime is 1666052197. The next prime is 1666052257. The reversal of 1666052209 is 9022506661.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 591851584 + 1074200625 = 24328^2 + 32775^2 .

It is a cyclic number.

It is not a de Polignac number, because 1666052209 - 2¹¹ = 1666050161 is a prime.

It is a super-2 number, since 2×1666052209² = 5551459926227559362, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1666052279) 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, 11411244 + ... + 11411389.

It is an arithmetic number, because the mean of its divisors is an integer number (422218729).

Almost surely, 2^1666052209 is an apocalyptic number.

It is an amenable number.

1666052209 is a deficient number, since it is larger than the sum of its proper divisors (22822707).

1666052209 is an equidigital number, since it uses as much as digits as its factorization.

1666052209 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 22822706.

The product of its (nonzero) digits is 38880, while the sum is 37.

The square root of 1666052209 is about 40817.3028138803. The cubic root of 1666052209 is about 1185.4853795632.

The spelling of 1666052209 in words is "one billion, six hundred sixty-six million, fifty-two thousand, two hundred nine".