81368661618633 has 16 divisors (see below), whose sum is σ = 110219954615360. Its totient is φ = 53383176354816.

The previous prime is 81368661618631. The next prime is 81368661618679. The reversal of 81368661618633 is 33681616686318.

It is not a de Polignac number, because 81368661618633 - 2¹ = 81368661618631 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (81368661618631) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 200401360 + ... + 200806977.

It is an arithmetic number, because the mean of its divisors is an integer number (6888747163460).

Almost surely, 2^{81368661618633} is an apocalyptic number.

It is an amenable number.

81368661618633 is a deficient number, since it is larger than the sum of its proper divisors (28851292996727).

81368661618633 is a wasteful number, since it uses less digits than its factorization.

81368661618633 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 401209416.

The product of its digits is 107495424, while the sum is 66.

The spelling of 81368661618633 in words is "eighty-one trillion, three hundred sixty-eight billion, six hundred sixty-one million, six hundred eighteen thousand, six hundred thirty-three".