81812211513 has 16 divisors (see below), whose sum is σ = 112016788800. Its totient is φ = 53081061120.

The previous prime is 81812211347. The next prime is 81812211521. The reversal of 81812211513 is 31511221818.

It is not a de Polignac number, because 81812211513 - 2¹⁸ = 81811949369 is a prime.

It is not an unprimeable number, because it can be changed into a prime (81812216513) 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 in 15 ways as a sum of consecutive naturals, for example, 762823 + ... + 863436.

It is an arithmetic number, because the mean of its divisors is an integer number (7001049300).

Almost surely, 2^81812211513 is an apocalyptic number.

It is an amenable number.

81812211513 is a deficient number, since it is larger than the sum of its proper divisors (30204577287).

81812211513 is a wasteful number, since it uses less digits than its factorization.

81812211513 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1626712.

The product of its digits is 3840, while the sum is 33.

The spelling of 81812211513 in words is "eighty-one billion, eight hundred twelve million, two hundred eleven thousand, five hundred thirteen".