81319280000 has 160 divisors (see below), whose sum is σ = 231360753360. Its totient is φ = 27880704000.

The previous prime is 81319279981. The next prime is 81319280027. The reversal of 81319280000 is 8291318.

It is a tau number, because it is divible by the number of its divisors (160).

It is a super-2 number, since 2×81319280000² (a number of 23 digits) contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (32).

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 19 ways as a sum of consecutive naturals, for example, 487394 + ... + 632606.

Almost surely, 2^81319280000 is an apocalyptic number.

81319280000 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 81319280000, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (115680376680).

81319280000 is an abundant number, since it is smaller than the sum of its proper divisors (150041473360).

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

81319280000 is an equidigital number, since it uses as much as digits as its factorization.

81319280000 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 145254 (or 145227 counting only the distinct ones).

The product of its (nonzero) digits is 3456, while the sum is 32.

The spelling of 81319280000 in words is "eighty-one billion, three hundred nineteen million, two hundred eighty thousand".