81749481705388 has 24 divisors (see below), whose sum is σ = 163499403398912. Its totient is φ = 35035397876304.

The previous prime is 81749481705361. The next prime is 81749481705427. The reversal of 81749481705388 is 88350718494718.

81749481705388 is digitally balanced in base 3, because in such base it contains all the possibile digits an equal number of times.

It is a super-5 number, since 5×81749481705388⁵ (a number of 71 digits) contains 55555 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 81749481705388.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 7216831 + ... + 14682697.

Almost surely, 2^{81749481705388} is an apocalyptic number.

It is an amenable number.

81749481705388 is an abundant number, since it is smaller than the sum of its proper divisors (81749921693524).

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

81749481705388 is a wasteful number, since it uses less digits than its factorization.

81749481705388 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7856941 (or 7856939 counting only the distinct ones).

The product of its (nonzero) digits is 433520640, while the sum is 73.

The spelling of 81749481705388 in words is "eighty-one trillion, seven hundred forty-nine billion, four hundred eighty-one million, seven hundred five thousand, three hundred eighty-eight".