81106517 has 2 divisors, whose sum is σ = 81106518. Its totient is φ = 81106516.

The previous prime is 81106499. The next prime is 81106549. The reversal of 81106517 is 71560118.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 76755121 + 4351396 = 8761^2 + 2086^2 .

It is a cyclic number.

It is not a de Polignac number, because 81106517 - 2¹⁴ = 81090133 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 81106517.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (81109517) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 40553258 + 40553259.

It is an arithmetic number, because the mean of its divisors is an integer number (40553259).

Almost surely, 2^81106517 is an apocalyptic number.

It is an amenable number.

81106517 is a deficient number, since it is larger than the sum of its proper divisors (1).

81106517 is an equidigital number, since it uses as much as digits as its factorization.

81106517 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 1680, while the sum is 29.

The square root of 81106517 is about 9005.9156669380. The cubic root of 81106517 is about 432.8644473969.

The spelling of 81106517 in words is "eighty-one million, one hundred six thousand, five hundred seventeen".