81075541 has 2 divisors, whose sum is σ = 81075542. Its totient is φ = 81075540.

The previous prime is 81075497. The next prime is 81075551. The reversal of 81075541 is 14557018.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 72607441 + 8468100 = 8521^2 + 2910^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-81075541 is a prime.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (81075551) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 40537770 + 40537771.

It is an arithmetic number, because the mean of its divisors is an integer number (40537771).

Almost surely, 2^81075541 is an apocalyptic number.

It is an amenable number.

81075541 is a deficient number, since it is larger than the sum of its proper divisors (1).

81075541 is an equidigital number, since it uses as much as digits as its factorization.

81075541 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 5600, while the sum is 31.

The square root of 81075541 is about 9004.1957442073. The cubic root of 81075541 is about 432.8093342077.

The spelling of 81075541 in words is "eighty-one million, seventy-five thousand, five hundred forty-one".