81942590481 has 4 divisors (see below), whose sum is σ = 109256787312. Its totient is φ = 54628393652.

The previous prime is 81942590441. The next prime is 81942590507. The reversal of 81942590481 is 18409524918.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 81942590481 - 2¹³ = 81942582289 is a prime.

It is a super-2 number, since 2×81942590481² (a number of 23 digits) contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (81942590441) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 13657098411 + ... + 13657098416.

It is an arithmetic number, because the mean of its divisors is an integer number (27314196828).

Almost surely, 2^81942590481 is an apocalyptic number.

It is an amenable number.

81942590481 is a deficient number, since it is larger than the sum of its proper divisors (27314196831).

81942590481 is a wasteful number, since it uses less digits than its factorization.

81942590481 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 27314196830.

The product of its (nonzero) digits is 829440, while the sum is 51.

The spelling of 81942590481 in words is "eighty-one billion, nine hundred forty-two million, five hundred ninety thousand, four hundred eighty-one".