81756511067 has 16 divisors (see below), whose sum is σ = 101944023552. Its totient is φ = 63697729920.

The previous prime is 81756511049. The next prime is 81756511069. The reversal of 81756511067 is 76011565718.

It is not a de Polignac number, because 81756511067 - 2⁶ = 81756511003 is a prime.

It is not an unprimeable number, because it can be changed into a prime (81756511069) 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, 531938 + ... + 668184.

It is an arithmetic number, because the mean of its divisors is an integer number (6371501472).

Almost surely, 2^81756511067 is an apocalyptic number.

81756511067 is a deficient number, since it is larger than the sum of its proper divisors (20187512485).

81756511067 is a wasteful number, since it uses less digits than its factorization.

81756511067 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 144058.

The product of its (nonzero) digits is 352800, while the sum is 47.

It can be divided in two parts, 8175651 and 1067, that added together give a palindrome (8176718).

The spelling of 81756511067 in words is "eighty-one billion, seven hundred fifty-six million, five hundred eleven thousand, sixty-seven".