667106681 has 2 divisors, whose sum is σ = 667106682. Its totient is φ = 667106680.

The previous prime is 667106647. The next prime is 667106683. The reversal of 667106681 is 186601766.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 666672400 + 434281 = 25820^2 + 659^2 .

It is a cyclic number.

It is not a de Polignac number, because 667106681 - 2¹⁴ = 667090297 is a prime.

It is a super-2 number, since 2×667106681² = 890062647669671522, which contains 22 as substring.

Together with 667106683, it forms a pair of twin primes.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (667106683) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 333553340 + 333553341.

It is an arithmetic number, because the mean of its divisors is an integer number (333553341).

Almost surely, 2^667106681 is an apocalyptic number.

It is an amenable number.

667106681 is a deficient number, since it is larger than the sum of its proper divisors (1).

667106681 is an equidigital number, since it uses as much as digits as its factorization.

667106681 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 72576, while the sum is 41.

The square root of 667106681 is about 25828.4084101208. The cubic root of 667106681 is about 873.7726164306.

The spelling of 667106681 in words is "six hundred sixty-seven million, one hundred six thousand, six hundred eighty-one".