666671831 has 4 divisors (see below), whose sum is σ = 761910672. Its totient is φ = 571432992.

The previous prime is 666671827. The next prime is 666671851. The reversal of 666671831 is 138176666.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 138176666 = 2 ⋅69088333.

It is a cyclic number.

It is not a de Polignac number, because 666671831 - 2² = 666671827 is a prime.

It is a super-2 number, since 2×666671831² = 888902660497785122, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (666671851) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 47619410 + ... + 47619423.

It is an arithmetic number, because the mean of its divisors is an integer number (190477668).

Almost surely, 2^666671831 is an apocalyptic number.

666671831 is a deficient number, since it is larger than the sum of its proper divisors (95238841).

666671831 is an equidigital number, since it uses as much as digits as its factorization.

666671831 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 95238840.

The product of its digits is 217728, while the sum is 44.

The square root of 666671831 is about 25819.9889814074. The cubic root of 666671831 is about 873.5827204608.

The spelling of 666671831 in words is "six hundred sixty-six million, six hundred seventy-one thousand, eight hundred thirty-one".