1666036941921 has 32 divisors (see below), whose sum is σ = 2695341398400. Its totient is φ = 1008685693440.

The previous prime is 1666036941913. The next prime is 1666036941953. The reversal of 1666036941921 is 1291496306661.

It is a happy number.

It is not a de Polignac number, because 1666036941921 - 2³ = 1666036941913 is a prime.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (1666036941721) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 2580636 + ... + 3160973.

It is an arithmetic number, because the mean of its divisors is an integer number (84229418700).

Almost surely, 2^{1666036941921} is an apocalyptic number.

1666036941921 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

It is an amenable number.

1666036941921 is a deficient number, since it is larger than the sum of its proper divisors (1029304456479).

1666036941921 is a wasteful number, since it uses less digits than its factorization.

1666036941921 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5742606 (or 5742600 counting only the distinct ones).

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

The spelling of 1666036941921 in words is "one trillion, six hundred sixty-six billion, thirty-six million, nine hundred forty-one thousand, nine hundred twenty-one".