81117529236 has 144 divisors (see below), whose sum is σ = 219399922560. Its totient is φ = 25196728320.

The previous prime is 81117529223. The next prime is 81117529289. The reversal of 81117529236 is 63292571118.

81117529236 is a `hidden beast` number, since 8 + 1 + 117 + 529 + 2 + 3 + 6 = 666.

It is a junction number, because it is equal to n+sod(n) for n = 81117529191 and 81117529200.

It is a congruent number.

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, 11076456 + ... + 11083776.

Almost surely, 2^81117529236 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 81117529236, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (109699961280).

81117529236 is an abundant number, since it is smaller than the sum of its proper divisors (138282393324).

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

81117529236 is a wasteful number, since it uses less digits than its factorization.

81117529236 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7614 (or 7609 counting only the distinct ones).

The product of its digits is 181440, while the sum is 45.

The spelling of 81117529236 in words is "eighty-one billion, one hundred seventeen million, five hundred twenty-nine thousand, two hundred thirty-six".