81558056736 has 768 divisors, whose sum is σ = 281652940800. Its totient is φ = 22759833600.

The previous prime is 81558056717. The next prime is 81558056821. The reversal of 81558056736 is 63765085518.

81558056736 is a `hidden beast` number, since 8 + 1 + 5 + 580 + 56 + 7 + 3 + 6 = 666.

It is a Harshad number since it is a multiple of its sum of digits (54).

It is an unprimeable number.

It is a polite number, since it can be written in 127 ways as a sum of consecutive naturals, for example, 414000190 + ... + 414000386.

It is an arithmetic number, because the mean of its divisors is an integer number (366735600).

Almost surely, 2^81558056736 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 81558056736, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (140826470400).

81558056736 is an abundant number, since it is smaller than the sum of its proper divisors (200094884064).

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

81558056736 is a wasteful number, since it uses less digits than its factorization.

81558056736 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 330 (or 316 counting only the distinct ones).

The product of its (nonzero) digits is 6048000, while the sum is 54.

The spelling of 81558056736 in words is "eighty-one billion, five hundred fifty-eight million, fifty-six thousand, seven hundred thirty-six".