81161096400 has 180 divisors, whose sum is σ = 281771669452. Its totient is φ = 21633730560.

The previous prime is 81161096399. The next prime is 81161096453. The reversal of 81161096400 is 469016118.

It is a happy number.

81161096400 is a `hidden beast` number, since 8 + 1 + 1 + 6 + 1 + 0 + 9 + 640 + 0 = 666.

It can be written as a sum of positive squares in 6 ways, for example, as 1494904896 + 79666191504 = 38664^2 + 282252^2 .

It is a tau number, because it is divible by the number of its divisors (180).

It is a Harshad number since it is a multiple of its sum of digits (36).

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, 14602422 + ... + 14607978.

Almost surely, 2^81161096400 is an apocalyptic number.

81161096400 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 81161096400, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (140885834726).

81161096400 is an abundant number, since it is smaller than the sum of its proper divisors (200610573052).

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

81161096400 is a wasteful number, since it uses less digits than its factorization.

81161096400 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9638 (or 9624 counting only the distinct ones).

The product of its (nonzero) digits is 10368, while the sum is 36.

The spelling of 81161096400 in words is "eighty-one billion, one hundred sixty-one million, ninety-six thousand, four hundred".