81665107 has 2 divisors, whose sum is σ = 81665108. Its totient is φ = 81665106.

The previous prime is 81665083. The next prime is 81665113. The reversal of 81665107 is 70156618.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 81665107 - 2¹¹ = 81663059 is a prime.

It is not a weakly prime, because it can be changed into another prime (81665117) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 40832553 + 40832554.

It is an arithmetic number, because the mean of its divisors is an integer number (40832554).

Almost surely, 2^81665107 is an apocalyptic number.

81665107 is a deficient number, since it is larger than the sum of its proper divisors (1).

81665107 is an equidigital number, since it uses as much as digits as its factorization.

81665107 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 10080, while the sum is 34.

The square root of 81665107 is about 9036.8748469811. The cubic root of 81665107 is about 433.8559040128.

The spelling of 81665107 in words is "eighty-one million, six hundred sixty-five thousand, one hundred seven".