81719668800 has 1680 divisors, whose sum is σ = 395126138880. Its totient is φ = 16049664000.

The previous prime is 81719668799. The next prime is 81719668837. The reversal of 81719668800 is 886691718.

It is a tau number, because it is divible by the number of its divisors (1680).

It is a Harshad number since it is a multiple of its sum of digits (54).

It is an unprimeable number.

It is a polite number, since it can be written in 239 ways as a sum of consecutive naturals, for example, 189604585 + ... + 189605015.

Almost surely, 2^81719668800 is an apocalyptic number.

81719668800 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 81719668800, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (197563069440).

81719668800 is an abundant number, since it is smaller than the sum of its proper divisors (313406470080).

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

81719668800 is a wasteful number, since it uses less digits than its factorization.

81719668800 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 502 (or 478 counting only the distinct ones).

The product of its (nonzero) digits is 1161216, while the sum is 54.

The spelling of 81719668800 in words is "eighty-one billion, seven hundred nineteen million, six hundred sixty-eight thousand, eight hundred".