1666685001667 has 4 divisors (see below), whose sum is σ = 1904782859056. Its totient is φ = 1428587144280.

The previous prime is 1666685001643. The next prime is 1666685001673. The reversal of 1666685001667 is 7661005866661.

It is a happy number.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1666685001667 is a prime.

It is not an unprimeable number, because it can be changed into a prime (1666685001677) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 119048928684 + ... + 119048928697.

It is an arithmetic number, because the mean of its divisors is an integer number (476195714764).

Almost surely, 2^{1666685001667} is an apocalyptic number.

1666685001667 is a deficient number, since it is larger than the sum of its proper divisors (238097857389).

1666685001667 is an equidigital number, since it uses as much as digits as its factorization.

1666685001667 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 238097857388.

The product of its (nonzero) digits is 13063680, while the sum is 58.

The spelling of 1666685001667 in words is "one trillion, six hundred sixty-six billion, six hundred eighty-five million, one thousand, six hundred sixty-seven".