1666779083563 has 4 divisors (see below), whose sum is σ = 1818304454808. Its totient is φ = 1515253712320.

The previous prime is 1666779083527. The next prime is 1666779083569. The reversal of 1666779083563 is 3653809776661.

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-1666779083563 is a prime.

It is a super-2 number, since 2×1666779083563² (a number of 25 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1666779083569) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 75762685606 + ... + 75762685627.

It is an arithmetic number, because the mean of its divisors is an integer number (454576113702).

Almost surely, 2^{1666779083563} is an apocalyptic number.

1666779083563 is a deficient number, since it is larger than the sum of its proper divisors (151525371245).

1666779083563 is a wasteful number, since it uses less digits than its factorization.

1666779083563 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 151525371244.

The product of its (nonzero) digits is 205752960, while the sum is 67.

The spelling of 1666779083563 in words is "one trillion, six hundred sixty-six billion, seven hundred seventy-nine million, eighty-three thousand, five hundred sixty-three".