81875641 has 2 divisors, whose sum is σ = 81875642. Its totient is φ = 81875640.

The previous prime is 81875611. The next prime is 81875669. The reversal of 81875641 is 14657818.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 46294416 + 35581225 = 6804^2 + 5965^2 .

It is a cyclic number.

It is not a de Polignac number, because 81875641 - 2⁵ = 81875609 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 81875594 and 81875603.

It is not a weakly prime, because it can be changed into another prime (81875611) 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 as a sum of consecutive naturals, namely, 40937820 + 40937821.

It is an arithmetic number, because the mean of its divisors is an integer number (40937821).

Almost surely, 2^81875641 is an apocalyptic number.

It is an amenable number.

81875641 is a deficient number, since it is larger than the sum of its proper divisors (1).

81875641 is an equidigital number, since it uses as much as digits as its factorization.

81875641 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 53760, while the sum is 40.

The square root of 81875641 is about 9048.5159556692. The cubic root of 81875641 is about 434.2284133225.

The spelling of 81875641 in words is "eighty-one million, eight hundred seventy-five thousand, six hundred forty-one".