71663847840 has 432 divisors, whose sum is σ = 269242639848. Its totient is φ = 17255043072.

The previous prime is 71663847821. The next prime is 71663847881. The reversal of 71663847840 is 4874836617.

71663847840 is a `hidden beast` number, since 7 + 166 + 3 + 8 + 478 + 4 + 0 = 666.

It can be written as a sum of positive squares in 4 ways, for example, as 42844032144 + 28819815696 = 206988^2 + 169764^2 .

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 71 ways as a sum of consecutive naturals, for example, 41351614 + ... + 41353346.

Almost surely, 2^71663847840 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 71663847840, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (134621319924).

71663847840 is an abundant number, since it is smaller than the sum of its proper divisors (197578792008).

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

71663847840 is a wasteful number, since it uses less digits than its factorization.

71663847840 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1861 (or 1803 counting only the distinct ones).

The product of its (nonzero) digits is 5419008, while the sum is 54.

The spelling of 71663847840 in words is "seventy-one billion, six hundred sixty-three million, eight hundred forty-seven thousand, eight hundred forty".