81171392000 has 320 divisors, whose sum is σ = 211054491648. Its totient is φ = 31104000000.

The previous prime is 81171391991. The next prime is 81171392063. The reversal of 81171392000 is 29317118.

It is a tau number, because it is divible by the number of its divisors (320).

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 (13) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 323391875 + ... + 323392125.

Almost surely, 2^81171392000 is an apocalyptic number.

81171392000 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 81171392000, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (105527245824).

81171392000 is an abundant number, since it is smaller than the sum of its proper divisors (129883099648).

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

81171392000 is a wasteful number, since it uses less digits than its factorization.

81171392000 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 478 (or 452 counting only the distinct ones).

The product of its (nonzero) digits is 3024, while the sum is 32.

The spelling of 81171392000 in words is "eighty-one billion, one hundred seventy-one million, three hundred ninety-two thousand".