81947405008224 has 432 divisors, whose sum is σ = 283130509006800. Its totient is φ = 22394623039488.

The previous prime is 81947405008211. The next prime is 81947405008321. The reversal of 81947405008224 is 42280050474918.

81947405008224 is a `hidden beast` number, since 8 + 1 + 9 + 4 + 7 + 405 + 0 + 0 + 8 + 224 = 666.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 71 ways as a sum of consecutive naturals, for example, 29476462 + ... + 32136530.

It is an arithmetic number, because the mean of its divisors is an integer number (655394696775).

Almost surely, 2^{81947405008224} is an apocalyptic number.

81947405008224 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 81947405008224, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (141565254503400).

81947405008224 is an abundant number, since it is smaller than the sum of its proper divisors (201183103998576).

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

81947405008224 is a wasteful number, since it uses less digits than its factorization.

81947405008224 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2660195 (or 2660177 counting only the distinct ones).

The product of its (nonzero) digits is 5160960, while the sum is 54.

The spelling of 81947405008224 in words is "eighty-one trillion, nine hundred forty-seven billion, four hundred five million, eight thousand, two hundred twenty-four".