81959841 has 6 divisors (see below), whose sum is σ = 118386450. Its totient is φ = 54639888.

The previous prime is 81959837. The next prime is 81959897. The reversal of 81959841 is 14895918.

81959841 is a `hidden beast` number, since 8 + 19 + 598 + 41 = 666.

It can be written as a sum of positive squares in only one way, i.e., 66585600 + 15374241 = 8160^2 + 3921^2 .

It is not a de Polignac number, because 81959841 - 2² = 81959837 is a prime.

It is not an unprimeable number, because it can be changed into a prime (81951841) 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 5 ways as a sum of consecutive naturals, for example, 4553316 + ... + 4553333.

It is an arithmetic number, because the mean of its divisors is an integer number (19731075).

Almost surely, 2^81959841 is an apocalyptic number.

It is an amenable number.

81959841 is a deficient number, since it is larger than the sum of its proper divisors (36426609).

81959841 is a wasteful number, since it uses less digits than its factorization.

81959841 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9106655 (or 9106652 counting only the distinct ones).

The product of its digits is 103680, while the sum is 45.

The square root of 81959841 is about 9053.1674567524. The cubic root of 81959841 is about 434.3772142185.

The spelling of 81959841 in words is "eighty-one million, nine hundred fifty-nine thousand, eight hundred forty-one".