66666657 has 8 divisors (see below), whose sum is σ = 90141120. Its totient is φ = 43818320.

The previous prime is 66666653. The next prime is 66666667. The reversal of 66666657 is 75666666.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 66666657 - 2² = 66666653 is a prime.

It is not an unprimeable number, because it can be changed into a prime (66666653) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 156282 + ... + 156707.

It is an arithmetic number, because the mean of its divisors is an integer number (11267640).

Almost surely, 2^66666657 is an apocalyptic number.

It is an amenable number.

66666657 is a deficient number, since it is larger than the sum of its proper divisors (23474463).

66666657 is a wasteful number, since it uses less digits than its factorization.

66666657 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 313063.

The product of its digits is 1632960, while the sum is 48.

The square root of 66666657 is about 8164.9652173172. The cubic root of 66666657 is about 405.4801134400.

Subtracting 66666657 from its reverse (75666666), we obtain a palindrome (9000009).

The spelling of 66666657 in words is "sixty-six million, six hundred sixty-six thousand, six hundred fifty-seven".