81505490227755 has 32 divisors (see below), whose sum is σ = 142284002526720. Its totient is φ = 39512292852480.

The previous prime is 81505490227747. The next prime is 81505490227783. The reversal of 81505490227755 is 55772209450518.

It is a happy number.

It is not a de Polignac number, because 81505490227755 - 2³ = 81505490227747 is a prime.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 33318882 + ... + 35681351.

It is an arithmetic number, because the mean of its divisors is an integer number (4446375078960).

Almost surely, 2^{81505490227755} is an apocalyptic number.

81505490227755 is a deficient number, since it is larger than the sum of its proper divisors (60778512298965).

81505490227755 is a wasteful number, since it uses less digits than its factorization.

81505490227755 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 69007411.

The product of its (nonzero) digits is 35280000, while the sum is 60.

The spelling of 81505490227755 in words is "eighty-one trillion, five hundred five billion, four hundred ninety million, two hundred twenty-seven thousand, seven hundred fifty-five".