1666210949 has 8 divisors (see below), whose sum is σ = 1794699480. Its totient is φ = 1537767936.

The previous prime is 1666210943. The next prime is 1666210961. The reversal of 1666210949 is 9490126661.

It can be written as a sum of positive squares in 4 ways, for example, as 527620900 + 1138590049 = 22970^2 + 33743^2 .

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 1666210949 - 2⁴ = 1666210933 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1666210943) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 127529 + ... + 139985.

It is an arithmetic number, because the mean of its divisors is an integer number (224337435).

Almost surely, 2^1666210949 is an apocalyptic number.

It is an amenable number.

1666210949 is a deficient number, since it is larger than the sum of its proper divisors (128488531).

1666210949 is a wasteful number, since it uses less digits than its factorization.

1666210949 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 22759.

The product of its (nonzero) digits is 139968, while the sum is 44.

The square root of 1666210949 is about 40819.2472860537. The cubic root of 1666210949 is about 1185.5230290382.

The spelling of 1666210949 in words is "one billion, six hundred sixty-six million, two hundred ten thousand, nine hundred forty-nine".