81243047424 has 480 divisors, whose sum is σ = 277273003392. Its totient is φ = 21076070400.

The previous prime is 81243047423. The next prime is 81243047429. The reversal of 81243047424 is 42474034218.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81243047423) by changing a digit.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 100175979 + ... + 100176789.

Almost surely, 2^81243047424 is an apocalyptic number.

81243047424 is a gapful number since it is divisible by the number (84) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 81243047424, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (138636501696).

81243047424 is an abundant number, since it is smaller than the sum of its proper divisors (196029955968).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

81243047424 is an equidigital number, since it uses as much as digits as its factorization.

81243047424 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 879 (or 834 counting only the distinct ones).

The product of its (nonzero) digits is 172032, while the sum is 39.

The spelling of 81243047424 in words is "eighty-one billion, two hundred forty-three million, forty-seven thousand, four hundred twenty-four".