81687308760 has 256 divisors, whose sum is σ = 299085696000. Its totient is φ = 19739427840.

The previous prime is 81687308713. The next prime is 81687308777. The reversal of 81687308760 is 6780378618.

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

It is a junction number, because it is equal to n+sod(n) for n = 81687308697 and 81687308706.

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 63 ways as a sum of consecutive naturals, for example, 385420 + ... + 558500.

It is an arithmetic number, because the mean of its divisors is an integer number (1168303500).

Almost surely, 2^81687308760 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 81687308760, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (149542848000).

81687308760 is an abundant number, since it is smaller than the sum of its proper divisors (217398387240).

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

81687308760 is a wasteful number, since it uses less digits than its factorization.

81687308760 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 173143 (or 173133 counting only the distinct ones).

The product of its (nonzero) digits is 2709504, while the sum is 54.

The spelling of 81687308760 in words is "eighty-one billion, six hundred eighty-seven million, three hundred eight thousand, seven hundred sixty".