81100800000 has 684 divisors, whose sum is σ = 319466943432. Its totient is φ = 19660800000.

The previous prime is 81100799993. The next prime is 81100800037. The reversal of 81100800000 is 800118.

It is a happy number.

It is a Harshad number since it is a multiple of its sum of digits (18).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 35 ways as a sum of consecutive naturals, for example, 7372799995 + ... + 7372800005.

Almost surely, 2^81100800000 is an apocalyptic number.

81100800000 is a gapful number since it is divisible by the number (80) 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 81100800000, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (159733471716).

81100800000 is an abundant number, since it is smaller than the sum of its proper divisors (238366143432).

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

81100800000 is an frugal number, since it uses more digits than its factorization.

81100800000 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 78 (or 21 counting only the distinct ones).

The product of its (nonzero) digits is 64, while the sum is 18.

The spelling of 81100800000 in words is "eighty-one billion, one hundred million, eight hundred thousand".