81516684218837 has 16 divisors (see below), whose sum is σ = 95145675164160. Its totient is φ = 68383680288768.

The previous prime is 81516684218819. The next prime is 81516684219101. The reversal of 81516684218837 is 73881248661518.

It is a cyclic number.

It is not a de Polignac number, because 81516684218837 - 2¹² = 81516684214741 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81516684218737) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 18058739 + ... + 22116767.

It is an arithmetic number, because the mean of its divisors is an integer number (5946604697760).

Almost surely, 2^{81516684218837} is an apocalyptic number.

It is an amenable number.

81516684218837 is a deficient number, since it is larger than the sum of its proper divisors (13628990945323).

81516684218837 is a wasteful number, since it uses less digits than its factorization.

81516684218837 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4119140.

The product of its digits is 123863040, while the sum is 68.

The spelling of 81516684218837 in words is "eighty-one trillion, five hundred sixteen billion, six hundred eighty-four million, two hundred eighteen thousand, eight hundred thirty-seven".