666985757 has 4 divisors (see below), whose sum is σ = 670841340. Its totient is φ = 663130176.

The previous prime is 666985727. The next prime is 666985799. The reversal of 666985757 is 757589666.

666985757 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 605848996 + 61136761 = 24614^2 + 7819^2 .

It is a cyclic number.

It is not a de Polignac number, because 666985757 - 2¹² = 666981661 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 666985696 and 666985705.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (666985727) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1927532 + ... + 1927877.

It is an arithmetic number, because the mean of its divisors is an integer number (167710335).

Almost surely, 2^666985757 is an apocalyptic number.

It is an amenable number.

666985757 is a deficient number, since it is larger than the sum of its proper divisors (3855583).

666985757 is a wasteful number, since it uses less digits than its factorization.

666985757 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3855582.

The product of its digits is 19051200, while the sum is 59.

The square root of 666985757 is about 25826.0673932366. The cubic root of 666985757 is about 873.7198180464.

The spelling of 666985757 in words is "six hundred sixty-six million, nine hundred eighty-five thousand, seven hundred fifty-seven".