81850051584 has 660 divisors, whose sum is σ = 288012556104. Its totient is φ = 23215030272.

The previous prime is 81850051583. The next prime is 81850051603. The reversal of 81850051584 is 48515005818.

81850051584 is a `hidden beast` number, since 8 + 1 + 8 + 50 + 0 + 515 + 84 = 666.

It is not an unprimeable number, because it can be changed into a prime (81850051583) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 59 ways as a sum of consecutive naturals, for example, 597445564 + ... + 597445700.

Almost surely, 2^81850051584 is an apocalyptic number.

81850051584 is a gapful number since it is divisible by the number (84) 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 81850051584, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (144006278052).

81850051584 is an abundant number, since it is smaller than the sum of its proper divisors (206162504520).

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

81850051584 is an frugal number, since it uses more digits than its factorization.

81850051584 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 200 (or 149 counting only the distinct ones).

The product of its (nonzero) digits is 256000, while the sum is 45.

The spelling of 81850051584 in words is "eighty-one billion, eight hundred fifty million, fifty-one thousand, five hundred eighty-four".