81361765466655 has 32 divisors (see below), whose sum is σ = 130592503627200. Its totient is φ = 43255054958592.

The previous prime is 81361765466593. The next prime is 81361765466659. The reversal of 81361765466655 is 55666456716318.

It is not a de Polignac number, because 81361765466655 - 2¹² = 81361765462559 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 81361765466655.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81361765466659) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 234766641 + ... + 235112949.

It is an arithmetic number, because the mean of its divisors is an integer number (4081015738350).

Almost surely, 2^{81361765466655} is an apocalyptic number.

81361765466655 is a deficient number, since it is larger than the sum of its proper divisors (49230738160545).

81361765466655 is a wasteful number, since it uses less digits than its factorization.

81361765466655 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 396043.

The product of its digits is 653184000, while the sum is 69.

The spelling of 81361765466655 in words is "eighty-one trillion, three hundred sixty-one billion, seven hundred sixty-five million, four hundred sixty-six thousand, six hundred fifty-five".