81708257280 has 208 divisors, whose sum is σ = 281547604800. Its totient is φ = 20112605184.

The previous prime is 81708257237. The next prime is 81708257317. The reversal of 81708257280 is 8275280718.

It is a tau number, because it is divible by the number of its divisors (208).

It is a Harshad number since it is a multiple of its sum of digits (48).

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 747571 + ... + 849869.

Almost surely, 2^81708257280 is an apocalyptic number.

81708257280 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 81708257280, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (140773802400).

81708257280 is an abundant number, since it is smaller than the sum of its proper divisors (199839347520).

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

81708257280 is a wasteful number, since it uses less digits than its factorization.

81708257280 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 102344 (or 102322 counting only the distinct ones).

The product of its (nonzero) digits is 501760, while the sum is 48.

The spelling of 81708257280 in words is "eighty-one billion, seven hundred eight million, two hundred fifty-seven thousand, two hundred eighty".