66756857 has 8 divisors (see below), whose sum is σ = 69940992. Its totient is φ = 63637200.

The previous prime is 66756847. The next prime is 66756863. The reversal of 66756857 is 75865766.

It is a happy number.

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 66756857 - 2¹⁶ = 66691321 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (66756847) 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, 13994 + ... + 18147.

It is an arithmetic number, because the mean of its divisors is an integer number (8742624).

Almost surely, 2^66756857 is an apocalyptic number.

66756857 is a gapful number since it is divisible by the number (67) formed by its first and last digit.

It is an amenable number.

66756857 is a deficient number, since it is larger than the sum of its proper divisors (3184135).

66756857 is a wasteful number, since it uses less digits than its factorization.

66756857 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 32239.

The product of its digits is 2116800, while the sum is 50.

The square root of 66756857 is about 8170.4869499926. The cubic root of 66756857 is about 405.6629025846.

The spelling of 66756857 in words is "sixty-six million, seven hundred fifty-six thousand, eight hundred fifty-seven".