666681841 has 16 divisors (see below), whose sum is σ = 822470400. Its totient is φ = 527744448.

The previous prime is 666681839. The next prime is 666681857. The reversal of 666681841 is 148186666.

It is not a de Polignac number, because 666681841 - 2¹ = 666681839 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 666681791 and 666681800.

It is not an unprimeable number, because it can be changed into a prime (666681811) 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 15 ways as a sum of consecutive naturals, for example, 66726 + ... + 76063.

It is an arithmetic number, because the mean of its divisors is an integer number (51404400).

Almost surely, 2^666681841 is an apocalyptic number.

It is an amenable number.

666681841 is a deficient number, since it is larger than the sum of its proper divisors (155788559).

666681841 is a wasteful number, since it uses less digits than its factorization.

666681841 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 142848.

The product of its digits is 331776, while the sum is 46.

The square root of 666681841 is about 25820.1828227455. The cubic root of 666681841 is about 873.5870926866.

The spelling of 666681841 in words is "six hundred sixty-six million, six hundred eighty-one thousand, eight hundred forty-one".