91781978569344 has 576 divisors, whose sum is σ = 320114107404000. Its totient is φ = 25136951906304.

The previous prime is 91781978569339. The next prime is 91781978569381. The reversal of 91781978569344 is 44396587918719.

91781978569344 is a `hidden beast` number, since 9 + 1 + 7 + 8 + 1 + 9 + 7 + 8 + 569 + 3 + 44 = 666.

It is a tau number, because it is divible by the number of its divisors (576).

It is an unprimeable number.

It is a polite number, since it can be written in 71 ways as a sum of consecutive naturals, for example, 227340207 + ... + 227743569.

Almost surely, 2^{91781978569344} 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 91781978569344, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (160057053702000).

91781978569344 is an abundant number, since it is smaller than the sum of its proper divisors (228332128834656).

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

91781978569344 is a wasteful number, since it uses less digits than its factorization.

91781978569344 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 403565 (or 403543 counting only the distinct ones).

The product of its digits is 3292047360, while the sum is 81.

The spelling of 91781978569344 in words is "ninety-one trillion, seven hundred eighty-one billion, nine hundred seventy-eight million, five hundred sixty-nine thousand, three hundred forty-four".