1666217273 has 8 divisors (see below), whose sum is σ = 1921719360. Its totient is φ = 1415082960.

The previous prime is 1666217269. The next prime is 1666217291. The reversal of 1666217273 is 3727126661.

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 1666217273 - 2² = 1666217269 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 1666217273.

It is not an unprimeable number, because it can be changed into a prime (1666217173) 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, 1091123 + ... + 1092648.

It is an arithmetic number, because the mean of its divisors is an integer number (240214920).

Almost surely, 2^1666217273 is an apocalyptic number.

It is an amenable number.

1666217273 is a deficient number, since it is larger than the sum of its proper divisors (255502087).

1666217273 is a wasteful number, since it uses less digits than its factorization.

1666217273 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2183887.

The product of its digits is 127008, while the sum is 41.

The square root of 1666217273 is about 40819.3247494370. The cubic root of 1666217273 is about 1185.5245288959.

The spelling of 1666217273 in words is "one billion, six hundred sixty-six million, two hundred seventeen thousand, two hundred seventy-three".