81374791680 has 1152 divisors, whose sum is σ = 359456348160. Its totient is φ = 16562257920.

The previous prime is 81374791669. The next prime is 81374791703. The reversal of 81374791680 is 8619747318.

81374791680 is a `hidden beast` number, since 8 + 1 + 3 + 7 + 479 + 168 + 0 = 666.

It is a tau number, because it is divible by the number of its divisors (1152).

It is an unprimeable number.

It is a polite number, since it can be written in 95 ways as a sum of consecutive naturals, for example, 259983204 + ... + 259983516.

It is an arithmetic number, because the mean of its divisors is an integer number (312028080).

Almost surely, 2^81374791680 is an apocalyptic number.

81374791680 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 81374791680, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (179728174080).

81374791680 is an abundant number, since it is smaller than the sum of its proper divisors (278081556480).

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

81374791680 is a wasteful number, since it uses less digits than its factorization.

81374791680 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 397 (or 374 counting only the distinct ones).

The product of its (nonzero) digits is 2032128, while the sum is 54.

The spelling of 81374791680 in words is "eighty-one billion, three hundred seventy-four million, seven hundred ninety-one thousand, six hundred eighty".