81159163200 has 252 divisors, whose sum is σ = 295169425408. Its totient is φ = 21138969600.

The previous prime is 81159163199. The next prime is 81159163219. The reversal of 81159163200 is 236195118.

81159163200 is a `hidden beast` number, since 8 + 1 + 1 + 591 + 63 + 2 + 0 + 0 = 666.

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 pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 35 ways as a sum of consecutive naturals, for example, 553665 + ... + 684735.

Almost surely, 2^81159163200 is an apocalyptic number.

81159163200 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 81159163200, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (147584712704).

81159163200 is an abundant number, since it is smaller than the sum of its proper divisors (214010262208).

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

81159163200 is a wasteful number, since it uses less digits than its factorization.

81159163200 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 131142 (or 131124 counting only the distinct ones).

The product of its (nonzero) digits is 12960, while the sum is 36.

The spelling of 81159163200 in words is "eighty-one billion, one hundred fifty-nine million, one hundred sixty-three thousand, two hundred".