66006891 has 6 divisors (see below), whose sum is σ = 95343300. Its totient is φ = 44004588.

The previous prime is 66006887. The next prime is 66006923. The reversal of 66006891 is 19860066.

It is not a de Polignac number, because 66006891 - 2² = 66006887 is a prime.

It is not an unprimeable number, because it can be changed into a prime (66006491) 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 5 ways as a sum of consecutive naturals, for example, 3667041 + ... + 3667058.

It is an arithmetic number, because the mean of its divisors is an integer number (15890550).

Almost surely, 2^66006891 is an apocalyptic number.

66006891 is a deficient number, since it is larger than the sum of its proper divisors (29336409).

66006891 is a wasteful number, since it uses less digits than its factorization.

66006891 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7334105 (or 7334102 counting only the distinct ones).

The product of its (nonzero) digits is 15552, while the sum is 36.

The square root of 66006891 is about 8124.4625052984. The cubic root of 66006891 is about 404.1380663126.

The spelling of 66006891 in words is "sixty-six million, six thousand, eight hundred ninety-one".