81678071523 has 16 divisors (see below), whose sum is σ = 116056912896. Its totient is φ = 50976383040.

The previous prime is 81678071521. The next prime is 81678071537. The reversal of 81678071523 is 32517087618.

It is a happy number.

It is not a de Polignac number, because 81678071523 - 2¹ = 81678071521 is a prime.

It is not an unprimeable number, because it can be changed into a prime (81678071521) 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, 12589738 + ... + 12596223.

It is an arithmetic number, because the mean of its divisors is an integer number (7253557056).

Almost surely, 2^81678071523 is an apocalyptic number.

81678071523 is a deficient number, since it is larger than the sum of its proper divisors (34378841373).

81678071523 is a wasteful number, since it uses less digits than its factorization.

81678071523 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 25186034.

The product of its (nonzero) digits is 564480, while the sum is 48.

The spelling of 81678071523 in words is "eighty-one billion, six hundred seventy-eight million, seventy-one thousand, five hundred twenty-three".