65666257 has 8 divisors (see below), whose sum is σ = 69916392. Its totient is φ = 61459200.

The previous prime is 65666213. The next prime is 65666273. The reversal of 65666257 is 75266656.

It can be written as a sum of positive squares in 4 ways, for example, as 18455616 + 47210641 = 4296^2 + 6871^2 .

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

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-65666257 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (65666057) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 7594 + ... + 13747.

It is an arithmetic number, because the mean of its divisors is an integer number (8739549).

Almost surely, 2^65666257 is an apocalyptic number.

It is an amenable number.

65666257 is a deficient number, since it is larger than the sum of its proper divisors (4250135).

65666257 is a wasteful number, since it uses less digits than its factorization.

65666257 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 21539.

The product of its digits is 453600, while the sum is 43.

The square root of 65666257 is about 8103.4719102370. The cubic root of 65666257 is about 403.4416710695.

The spelling of 65666257 in words is "sixty-five million, six hundred sixty-six thousand, two hundred fifty-seven".