81113628672 has 360 divisors, whose sum is σ = 243457761456. Its totient is φ = 26008879104.

The previous prime is 81113628671. The next prime is 81113628683. The reversal of 81113628672 is 27682631118.

81113628672 is a `hidden beast` number, since 8 + 1 + 1 + 13 + 628 + 6 + 7 + 2 = 666.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81113628671) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 758071243 + ... + 758071349.

Almost surely, 2^81113628672 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 81113628672, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (121728880728).

81113628672 is an abundant number, since it is smaller than the sum of its proper divisors (162344132784).

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

81113628672 is a wasteful number, since it uses less digits than its factorization.

81113628672 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 291 (or 262 counting only the distinct ones).

The product of its digits is 193536, while the sum is 45.

The spelling of 81113628672 in words is "eighty-one billion, one hundred thirteen million, six hundred twenty-eight thousand, six hundred seventy-two".