81572515885749 has 64 divisors (see below), whose sum is σ = 135080667187200. Its totient is φ = 42719068846080.

The previous prime is 81572515885747. The next prime is 81572515885753. The reversal of 81572515885749 is 94758851527518.

It is not a de Polignac number, because 81572515885749 - 2¹ = 81572515885747 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81572515885747) by changing a digit.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 2327202 + ... + 12983100.

It is an arithmetic number, because the mean of its divisors is an integer number (2110635424800).

Almost surely, 2^{81572515885749} is an apocalyptic number.

It is an amenable number.

81572515885749 is a deficient number, since it is larger than the sum of its proper divisors (53508151301451).

81572515885749 is a wasteful number, since it uses less digits than its factorization.

81572515885749 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10656490.

The product of its digits is 1128960000, while the sum is 75.

The spelling of 81572515885749 in words is "eighty-one trillion, five hundred seventy-two billion, five hundred fifteen million, eight hundred eighty-five thousand, seven hundred forty-nine".