81872140145 has 16 divisors (see below), whose sum is σ = 98883992592. Its totient is φ = 65073296640.

The previous prime is 81872140123. The next prime is 81872140153. The reversal of 81872140145 is 54104127818.

It can be written as a sum of positive squares in 8 ways, for example, as 40298153536 + 41573986609 = 200744^2 + 203897^2 .

It is not a de Polignac number, because 81872140145 - 2⁶ = 81872140081 is a prime.

It is a Duffinian number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 1224275 + ... + 1289415.

It is an arithmetic number, because the mean of its divisors is an integer number (6180249537).

Almost surely, 2^81872140145 is an apocalyptic number.

It is an amenable number.

81872140145 is a deficient number, since it is larger than the sum of its proper divisors (17011852447).

81872140145 is a wasteful number, since it uses less digits than its factorization.

81872140145 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 66772.

The product of its (nonzero) digits is 71680, while the sum is 41.

The spelling of 81872140145 in words is "eighty-one billion, eight hundred seventy-two million, one hundred forty thousand, one hundred forty-five".