81857755441 has 16 divisors (see below), whose sum is σ = 102741379200. Its totient is φ = 63357166080.

The previous prime is 81857755361. The next prime is 81857755457. The reversal of 81857755441 is 14455775818.

It is a cyclic number.

It is not a de Polignac number, because 81857755441 - 2¹⁵ = 81857722673 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (81857755471) 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, 3555936 + ... + 3578881.

It is an arithmetic number, because the mean of its divisors is an integer number (6421336200).

Almost surely, 2^81857755441 is an apocalyptic number.

It is an amenable number.

81857755441 is a deficient number, since it is larger than the sum of its proper divisors (20883623759).

81857755441 is a wasteful number, since it uses less digits than its factorization.

81857755441 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7134984.

The product of its digits is 6272000, while the sum is 55.

The spelling of 81857755441 in words is "eighty-one billion, eight hundred fifty-seven million, seven hundred fifty-five thousand, four hundred forty-one".