668543831 has 2 divisors, whose sum is σ = 668543832. Its totient is φ = 668543830.

The previous prime is 668543803. The next prime is 668543857. The reversal of 668543831 is 138345866.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 668543831 - 2⁶ = 668543767 is a prime.

It is a super-2 number, since 2×668543831² = 893901707936313122, which contains 22 as substring.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (668543131) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 334271915 + 334271916.

It is an arithmetic number, because the mean of its divisors is an integer number (334271916).

Almost surely, 2^668543831 is an apocalyptic number.

668543831 is a deficient number, since it is larger than the sum of its proper divisors (1).

668543831 is an equidigital number, since it uses as much as digits as its factorization.

668543831 is an evil number, because the sum of its binary digits is even.

The product of its digits is 414720, while the sum is 44.

The square root of 668543831 is about 25856.2145527918. The cubic root of 668543831 is about 874.3996234143.

The spelling of 668543831 in words is "six hundred sixty-eight million, five hundred forty-three thousand, eight hundred thirty-one".