1666851685000 has 40 divisors (see below), whose sum is σ = 3905433509670. Its totient is φ = 666740672000.

The previous prime is 1666851684997. The next prime is 1666851685001. The reversal of 1666851685000 is 5861586661.

It can be written as a sum of positive squares in 5 ways, for example, as 227989060324 + 1438862624676 = 477482^2 + 1199526^2 .

It is a tau number, because it is divible by the number of its divisors (40).

It is not an unprimeable number, because it can be changed into a prime (1666851685001) by changing a digit.

It is a polite number, since it can be written in 9 ways as a sum of consecutive naturals, for example, 166680169 + ... + 166690168.

Almost surely, 2^{1666851685000} is an apocalyptic number.

1666851685000 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

1666851685000 is an abundant number, since it is smaller than the sum of its proper divisors (2238581824670).

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

1666851685000 is an equidigital number, since it uses as much as digits as its factorization.

1666851685000 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 333370363 (or 333370344 counting only the distinct ones).

The product of its (nonzero) digits is 2073600, while the sum is 52.

The spelling of 1666851685000 in words is "one trillion, six hundred sixty-six billion, eight hundred fifty-one million, six hundred eighty-five thousand".