81424051800 has 768 divisors, whose sum is σ = 322646016000. Its totient is φ = 16529909760.

The previous prime is 81424051777. The next prime is 81424051867. The reversal of 81424051800 is 815042418.

It is a Cunningham number, because it is equal to 285349²-1.

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 191 ways as a sum of consecutive naturals, for example, 185475981 + ... + 185476419.

It is an arithmetic number, because the mean of its divisors is an integer number (420112000).

Almost surely, 2^81424051800 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 81424051800, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (161323008000).

81424051800 is an abundant number, since it is smaller than the sum of its proper divisors (241221964200).

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

81424051800 is a wasteful number, since it uses less digits than its factorization.

81424051800 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 600 (or 591 counting only the distinct ones).

The product of its (nonzero) digits is 10240, while the sum is 33.

The spelling of 81424051800 in words is "eighty-one billion, four hundred twenty-four million, fifty-one thousand, eight hundred".