81366671 has 2 divisors, whose sum is σ = 81366672. Its totient is φ = 81366670.

The previous prime is 81366613. The next prime is 81366689. The reversal of 81366671 is 17666318.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-81366671 is a prime.

It is a Sophie Germain prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (81366611) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 40683335 + 40683336.

It is an arithmetic number, because the mean of its divisors is an integer number (40683336).

Almost surely, 2^81366671 is an apocalyptic number.

81366671 is a deficient number, since it is larger than the sum of its proper divisors (1).

81366671 is an equidigital number, since it uses as much as digits as its factorization.

81366671 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 36288, while the sum is 38.

The square root of 81366671 is about 9020.3476097099. The cubic root of 81366671 is about 433.3267663042.

The spelling of 81366671 in words is "eighty-one million, three hundred sixty-six thousand, six hundred seventy-one".