81682217 has 2 divisors, whose sum is σ = 81682218. Its totient is φ = 81682216.

The previous prime is 81682201. The next prime is 81682231. The reversal of 81682217 is 71228618.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 72777961 + 8904256 = 8531^2 + 2984^2 .

It is a cyclic number.

It is not a de Polignac number, because 81682217 - 2⁴ = 81682201 is a prime.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (81682267) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 40841108 + 40841109.

It is an arithmetic number, because the mean of its divisors is an integer number (40841109).

Almost surely, 2^81682217 is an apocalyptic number.

It is an amenable number.

81682217 is a deficient number, since it is larger than the sum of its proper divisors (1).

81682217 is an equidigital number, since it uses as much as digits as its factorization.

81682217 is an evil number, because the sum of its binary digits is even.

The product of its digits is 10752, while the sum is 35.

The square root of 81682217 is about 9037.8214742271. The cubic root of 81682217 is about 433.8862015553.

The spelling of 81682217 in words is "eighty-one million, six hundred eighty-two thousand, two hundred seventeen".