1666871887 has 4 divisors (see below), whose sum is σ = 1667942640. Its totient is φ = 1665801136.

The previous prime is 1666871861. The next prime is 1666871911. The reversal of 1666871887 is 7881786661.

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-1666871887 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1666871287) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 533038 + ... + 536155.

It is an arithmetic number, because the mean of its divisors is an integer number (416985660).

Almost surely, 2^1666871887 is an apocalyptic number.

1666871887 is a deficient number, since it is larger than the sum of its proper divisors (1070753).

1666871887 is a wasteful number, since it uses less digits than its factorization.

1666871887 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1070752.

The product of its digits is 5419008, while the sum is 58.

The square root of 1666871887 is about 40827.3423945277. The cubic root of 1666871887 is about 1185.6797626215.

The spelling of 1666871887 in words is "one billion, six hundred sixty-six million, eight hundred seventy-one thousand, eight hundred eighty-seven".