1666685010001 has 6 divisors (see below), whose sum is σ = 1831976085506. Its totient is φ = 1515168190800.

The previous prime is 1666685009959. The next prime is 1666685010037. The reversal of 1666685010001 is 1000105866661.

It is a happy number.

It can be written as a sum of positive squares in only one way, i.e., 1608333776401 + 58351233600 = 1268201^2 + 241560^2 .

It is not a de Polignac number, because 1666685010001 - 2³³ = 1658095075409 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1666685110001) 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 5 ways as a sum of consecutive naturals, for example, 6887128020 + ... + 6887128261.

Almost surely, 2^{1666685010001} is an apocalyptic number.

1666685010001 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

It is an amenable number.

1666685010001 is a deficient number, since it is larger than the sum of its proper divisors (165291075505).

1666685010001 is a wasteful number, since it uses less digits than its factorization.

1666685010001 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 13774256303 (or 13774256292 counting only the distinct ones).

The product of its (nonzero) digits is 51840, while the sum is 40.

The spelling of 1666685010001 in words is "one trillion, six hundred sixty-six billion, six hundred eighty-five million, ten thousand, one".