81811820449800 has 144 divisors (see below), whose sum is σ = 314001558536640. Its totient is φ = 18699844671360.

The previous prime is 81811820449771. The next prime is 81811820449817. The reversal of 81811820449800 is 894402811818.

It is a happy number.

81811820449800 is a `hidden beast` number, since 8 + 1 + 8 + 118 + 2 + 0 + 449 + 80 + 0 = 666.

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, 3246488212 + ... + 3246513411.

Almost surely, 2^{81811820449800} is an apocalyptic number.

It is an amenable number.

81811820449800 is an abundant number, since it is smaller than the sum of its proper divisors (232189738086840).

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

81811820449800 is a wasteful number, since it uses less digits than its factorization.

81811820449800 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6493001652 (or 6493001640 counting only the distinct ones).

The product of its (nonzero) digits is 1179648, while the sum is 54.

The spelling of 81811820449800 in words is "eighty-one trillion, eight hundred eleven billion, eight hundred twenty million, four hundred forty-nine thousand, eight hundred".