81543724441 has 16 divisors (see below), whose sum is σ = 87260169024. Its totient is φ = 75930015744.

The previous prime is 81543724421. The next prime is 81543724547. The reversal of 81543724441 is 14442734518.

It is a cyclic number.

It is not a de Polignac number, because 81543724441 - 2⁹ = 81543723929 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (81543724421) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 6264646 + ... + 6277648.

It is an arithmetic number, because the mean of its divisors is an integer number (5453760564).

Almost surely, 2^81543724441 is an apocalyptic number.

It is an amenable number.

81543724441 is a deficient number, since it is larger than the sum of its proper divisors (5716444583).

81543724441 is a wasteful number, since it uses less digits than its factorization.

81543724441 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 16920.

The product of its digits is 430080, while the sum is 43.

The spelling of 81543724441 in words is "eighty-one billion, five hundred forty-three million, seven hundred twenty-four thousand, four hundred forty-one".