81836930672640 has 2688 divisors, whose sum is σ = 357177648522240. Its totient is φ = 17715245875200.

The previous prime is 81836930672593. The next prime is 81836930672659. The reversal of 81836930672640 is 4627603963818.

81836930672640 is a `hidden beast` number, since 8 + 1 + 8 + 3 + 69 + 306 + 7 + 264 + 0 = 666.

It is an unprimeable number.

It is a polite number, since it can be written in 223 ways as a sum of consecutive naturals, for example, 33092166444 + ... + 33092168916.

It is an arithmetic number, because the mean of its divisors is an integer number (132878589480).

Almost surely, 2^{81836930672640} is an apocalyptic number.

81836930672640 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 81836930672640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (178588824261120).

81836930672640 is an abundant number, since it is smaller than the sum of its proper divisors (275340717849600).

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

81836930672640 is a wasteful number, since it uses less digits than its factorization.

81836930672640 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2573 (or 2538 counting only the distinct ones).

The product of its (nonzero) digits is 62705664, while the sum is 63.

The spelling of 81836930672640 in words is "eighty-one trillion, eight hundred thirty-six billion, nine hundred thirty million, six hundred seventy-two thousand, six hundred forty".