66697857 has 16 divisors (see below), whose sum is σ = 101223360. Its totient is φ = 43380000.

The previous prime is 66697843. The next prime is 66697871. The reversal of 66697857 is 75879666.

It is a happy number.

It is an interprime number because it is at equal distance from previous prime (66697843) and next prime (66697871).

It is not a de Polignac number, because 66697857 - 2¹⁵ = 66665089 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (66697457) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 29019 + ... + 31232.

It is an arithmetic number, because the mean of its divisors is an integer number (6326460).

Almost surely, 2^66697857 is an apocalyptic number.

It is an amenable number.

66697857 is a deficient number, since it is larger than the sum of its proper divisors (34525503).

66697857 is a wasteful number, since it uses less digits than its factorization.

66697857 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 60301 (or 60295 counting only the distinct ones).

The product of its digits is 3810240, while the sum is 54.

The square root of 66697857 is about 8166.8755959669. The cubic root of 66697857 is about 405.5433584817.

The spelling of 66697857 in words is "sixty-six million, six hundred ninety-seven thousand, eight hundred fifty-seven".