81147643200 has 1008 divisors, whose sum is σ = 331829761536. Its totient is φ = 18653184000.

The previous prime is 81147643163. The next prime is 81147643207. The reversal of 81147643200 is 234674118.

81147643200 is a `hidden beast` number, since 8 + 1 + 1 + 4 + 7 + 643 + 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 not an unprimeable number, because it can be changed into a prime (81147643207) by changing a digit.

It is a polite number, since it can be written in 143 ways as a sum of consecutive naturals, for example, 202363000 + ... + 202363400.

It is an arithmetic number, because the mean of its divisors is an integer number (329196192).

Almost surely, 2^81147643200 is an apocalyptic number.

81147643200 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 81147643200, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (165914880768).

81147643200 is an abundant number, since it is smaller than the sum of its proper divisors (250682118336).

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

81147643200 is a wasteful number, since it uses less digits than its factorization.

81147643200 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 512 (or 494 counting only the distinct ones).

The product of its (nonzero) digits is 32256, while the sum is 36.

The spelling of 81147643200 in words is "eighty-one billion, one hundred forty-seven million, six hundred forty-three thousand, two hundred".