81998520000 has 280 divisors, whose sum is σ = 273637095600. Its totient is φ = 21662208000.

The previous prime is 81998519983. The next prime is 81998520047. The reversal of 81998520000 is 2589918.

It is a happy number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 39 ways as a sum of consecutive naturals, for example, 13076866 + ... + 13083134.

Almost surely, 2^81998520000 is an apocalyptic number.

81998520000 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 81998520000, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (136818547800).

81998520000 is an abundant number, since it is smaller than the sum of its proper divisors (191638575600).

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

81998520000 is a wasteful number, since it uses less digits than its factorization.

81998520000 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6413 (or 6388 counting only the distinct ones).

The product of its (nonzero) digits is 51840, while the sum is 42.

The spelling of 81998520000 in words is "eighty-one billion, nine hundred ninety-eight million, five hundred twenty thousand".