81186653 has 2 divisors, whose sum is σ = 81186654. Its totient is φ = 81186652.

The previous prime is 81186643. The next prime is 81186661. The reversal of 81186653 is 35668118.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 80604484 + 582169 = 8978^2 + 763^2 .

It is a cyclic number.

It is not a de Polignac number, because 81186653 - 2⁸ = 81186397 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (81186643) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 40593326 + 40593327.

It is an arithmetic number, because the mean of its divisors is an integer number (40593327).

Almost surely, 2^81186653 is an apocalyptic number.

It is an amenable number.

81186653 is a deficient number, since it is larger than the sum of its proper divisors (1).

81186653 is an equidigital number, since it uses as much as digits as its factorization.

81186653 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 34560, while the sum is 38.

The square root of 81186653 is about 9010.3636441600. The cubic root of 81186653 is about 433.0069620743.

The spelling of 81186653 in words is "eighty-one million, one hundred eighty-six thousand, six hundred fifty-three".