1666668887 has 4 divisors (see below), whose sum is σ = 1794874200. Its totient is φ = 1538463576.

The previous prime is 1666668881. The next prime is 1666668911. The reversal of 1666668887 is 7888666661.

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

It is not a de Polignac number, because 1666668887 - 2⁶ = 1666668823 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 (1666668881) 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, 64102637 + ... + 64102662.

It is an arithmetic number, because the mean of its divisors is an integer number (448718550).

Almost surely, 2^1666668887 is an apocalyptic number.

1666668887 is a deficient number, since it is larger than the sum of its proper divisors (128205313).

1666668887 is a wasteful number, since it uses less digits than its factorization.

1666668887 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 128205312.

The product of its digits is 27869184, while the sum is 62.

The square root of 1666668887 is about 40824.8562397959. The cubic root of 1666668887 is about 1185.6316279957.

The spelling of 1666668887 in words is "one billion, six hundred sixty-six million, six hundred sixty-eight thousand, eight hundred eighty-seven".