81768589475328 has 2560 divisors, whose sum is σ = 305466163200000. Its totient is φ = 21099573411840.

The previous prime is 81768589475327. The next prime is 81768589475369. The reversal of 81768589475328 is 82357498586718.

81768589475328 is a `hidden beast` number, since 8 + 1 + 7 + 6 + 8 + 589 + 4 + 7 + 5 + 3 + 28 = 666.

It is a super-2 number, since 2×81768589475328² (a number of 29 digits) contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81768589475327) by changing a digit.

It is a polite number, since it can be written in 255 ways as a sum of consecutive naturals, for example, 456807762343 + ... + 456807762521.

It is an arithmetic number, because the mean of its divisors is an integer number (119322720000).

Almost surely, 2^{81768589475328} 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 81768589475328, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (152733081600000).

81768589475328 is an abundant number, since it is smaller than the sum of its proper divisors (223697573724672).

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

81768589475328 is a wasteful number, since it uses less digits than its factorization.

81768589475328 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 421 (or 399 counting only the distinct ones).

The product of its digits is 6502809600, while the sum is 81.

The spelling of 81768589475328 in words is "eighty-one trillion, seven hundred sixty-eight billion, five hundred eighty-nine million, four hundred seventy-five thousand, three hundred twenty-eight".