81766673 has 2 divisors, whose sum is σ = 81766674. Its totient is φ = 81766672.

The previous prime is 81766667. The next prime is 81766681. The reversal of 81766673 is 37666718.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 66455104 + 15311569 = 8152^2 + 3913^2 .

It is a cyclic number.

It is not a de Polignac number, because 81766673 - 2⁶ = 81766609 is a prime.

It is a Sophie Germain prime.

It is a Curzon number.

It is not a weakly prime, because it can be changed into another prime (81766613) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 40883336 + 40883337.

It is an arithmetic number, because the mean of its divisors is an integer number (40883337).

Almost surely, 2^81766673 is an apocalyptic number.

It is an amenable number.

81766673 is a deficient number, since it is larger than the sum of its proper divisors (1).

81766673 is an equidigital number, since it uses as much as digits as its factorization.

81766673 is an evil number, because the sum of its binary digits is even.

The product of its digits is 254016, while the sum is 44.

The square root of 81766673 is about 9042.4926320125. The cubic root of 81766673 is about 434.0356901143.

The spelling of 81766673 in words is "eighty-one million, seven hundred sixty-six thousand, six hundred seventy-three".