666394751 has 8 divisors (see below), whose sum is σ = 727166208. Its totient is φ = 605655000.

The previous prime is 666394739. The next prime is 666394777. The reversal of 666394751 is 157493666.

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-666394751 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 666394696 and 666394705.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (666397751) 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, 66266 + ... + 75656.

It is an arithmetic number, because the mean of its divisors is an integer number (90895776).

Almost surely, 2^666394751 is an apocalyptic number.

666394751 is a deficient number, since it is larger than the sum of its proper divisors (60771457).

666394751 is a wasteful number, since it uses less digits than its factorization.

666394751 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 15853.

The product of its digits is 816480, while the sum is 47.

The square root of 666394751 is about 25814.6228134366. The cubic root of 666394751 is about 873.4616784777.

The spelling of 666394751 in words is "six hundred sixty-six million, three hundred ninety-four thousand, seven hundred fifty-one".