81368653 has 2 divisors, whose sum is σ = 81368654. Its totient is φ = 81368652.

The previous prime is 81368593. The next prime is 81368669. The reversal of 81368653 is 35686318.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 51796809 + 29571844 = 7197^2 + 5438^2 .

It is a cyclic number.

It is not a de Polignac number, because 81368653 - 2¹⁷ = 81237581 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (81308653) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 40684326 + 40684327.

It is an arithmetic number, because the mean of its divisors is an integer number (40684327).

Almost surely, 2^81368653 is an apocalyptic number.

It is an amenable number.

81368653 is a deficient number, since it is larger than the sum of its proper divisors (1).

81368653 is an equidigital number, since it uses as much as digits as its factorization.

81368653 is an evil number, because the sum of its binary digits is even.

The product of its digits is 103680, while the sum is 40.

The square root of 81368653 is about 9020.4574717694. The cubic root of 81368653 is about 433.3302847254.

The spelling of 81368653 in words is "eighty-one million, three hundred sixty-eight thousand, six hundred fifty-three".