1666005432785 has 16 divisors (see below), whose sum is σ = 2063772019200. Its totient is φ = 1289763803520.

The previous prime is 1666005432769. The next prime is 1666005432827. The reversal of 1666005432785 is 5872345006661.

It is a happy number.

It is not a de Polignac number, because 1666005432785 - 2⁴ = 1666005432769 is a prime.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 4439141 + ... + 4799789.

It is an arithmetic number, because the mean of its divisors is an integer number (128985751200).

Almost surely, 2^{1666005432785} is an apocalyptic number.

It is an amenable number.

1666005432785 is a deficient number, since it is larger than the sum of its proper divisors (397766586415).

1666005432785 is a wasteful number, since it uses less digits than its factorization.

1666005432785 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 390488.

The product of its (nonzero) digits is 7257600, while the sum is 53.

The spelling of 1666005432785 in words is "one trillion, six hundred sixty-six billion, five million, four hundred thirty-two thousand, seven hundred eighty-five".