81787357180668 has 12 divisors (see below), whose sum is σ = 190837166754920. Its totient is φ = 27262452393552.

The previous prime is 81787357180651. The next prime is 81787357180691. The reversal of 81787357180668 is 86608175378718.

It is a tau number, because it is divible by the number of its divisors (12).

It is a self number, because there is not a number n which added to its sum of digits gives 81787357180668.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 3407806549183 + ... + 3407806549206.

Almost surely, 2^{81787357180668} is an apocalyptic number.

It is an amenable number.

81787357180668 is an abundant number, since it is smaller than the sum of its proper divisors (109049809574252).

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

81787357180668 is a wasteful number, since it uses less digits than its factorization.

81787357180668 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6815613098396 (or 6815613098394 counting only the distinct ones).

The product of its (nonzero) digits is 758661120, while the sum is 75.

The spelling of 81787357180668 in words is "eighty-one trillion, seven hundred eighty-seven billion, three hundred fifty-seven million, one hundred eighty thousand, six hundred sixty-eight".