1666649916 has 18 divisors (see below), whose sum is σ = 4212920712. Its totient is φ = 555549960.

The previous prime is 1666649911. The next prime is 1666649917. The reversal of 1666649916 is 6199466661.

It is a tau number, because it is divible by the number of its divisors (18).

It is a nude number because it is divisible by every one of its digits.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1666649911) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 23147880 + ... + 23147951.

Almost surely, 2^1666649916 is an apocalyptic number.

It is an amenable number.

1666649916 is an abundant number, since it is smaller than the sum of its proper divisors (2546270796).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

1666649916 is a wasteful number, since it uses less digits than its factorization.

1666649916 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 46295841 (or 46295836 counting only the distinct ones).

The product of its digits is 2519424, while the sum is 54.

The square root of 1666649916 is about 40824.6238929399. The cubic root of 1666649916 is about 1185.6271294611.

The spelling of 1666649916 in words is "one billion, six hundred sixty-six million, six hundred forty-nine thousand, nine hundred sixteen".