81366871 has 2 divisors, whose sum is σ = 81366872. Its totient is φ = 81366870.

The previous prime is 81366839. The next prime is 81366889. The reversal of 81366871 is 17866318.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 81366871 - 2⁵ = 81366839 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (81366671) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 40683435 + 40683436.

It is an arithmetic number, because the mean of its divisors is an integer number (40683436).

Almost surely, 2^81366871 is an apocalyptic number.

81366871 is a deficient number, since it is larger than the sum of its proper divisors (1).

81366871 is an equidigital number, since it uses as much as digits as its factorization.

81366871 is an evil number, because the sum of its binary digits is even.

The product of its digits is 48384, while the sum is 40.

The square root of 81366871 is about 9020.3586957504. The cubic root of 81366871 is about 433.3271213442.

The spelling of 81366871 in words is "eighty-one million, three hundred sixty-six thousand, eight hundred seventy-one".