81240584256 has 336 divisors, whose sum is σ = 273762216000. Its totient is φ = 23680346112.

The previous prime is 81240584219. The next prime is 81240584273. The reversal of 81240584256 is 65248504218.

81240584256 is a `hidden beast` number, since 8 + 1 + 2 + 40 + 584 + 25 + 6 = 666.

It is an unprimeable number.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 3830770 + ... + 3851918.

It is an arithmetic number, because the mean of its divisors is an integer number (814768500).

Almost surely, 2^81240584256 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 81240584256, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (136881108000).

81240584256 is an abundant number, since it is smaller than the sum of its proper divisors (192521631744).

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

81240584256 is a wasteful number, since it uses less digits than its factorization.

81240584256 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 21208 (or 21186 counting only the distinct ones).

The product of its (nonzero) digits is 614400, while the sum is 45.

The spelling of 81240584256 in words is "eighty-one billion, two hundred forty million, five hundred eighty-four thousand, two hundred fifty-six".