81944543 has 2 divisors, whose sum is σ = 81944544. Its totient is φ = 81944542.

The previous prime is 81944521. The next prime is 81944557. The reversal of 81944543 is 34544918.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 81944543 - 2⁶ = 81944479 is a prime.

It is a super-3 number, since 3×81944543³ (a number of 25 digits) contains 333 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 81944497 and 81944506.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (81944143) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 40972271 + 40972272.

It is an arithmetic number, because the mean of its divisors is an integer number (40972272).

Almost surely, 2^81944543 is an apocalyptic number.

81944543 is a deficient number, since it is larger than the sum of its proper divisors (1).

81944543 is an equidigital number, since it uses as much as digits as its factorization.

81944543 is an evil number, because the sum of its binary digits is even.

The product of its digits is 69120, while the sum is 38.

The square root of 81944543 is about 9052.3225196631. The cubic root of 81944543 is about 434.3501866888.

The spelling of 81944543 in words is "eighty-one million, nine hundred forty-four thousand, five hundred forty-three".