81163706872 has 8 divisors (see below), whose sum is σ = 152181950400. Its totient is φ = 40581853432.

The previous prime is 81163706867. The next prime is 81163706879. The reversal of 81163706872 is 27860736118.

It is a happy number.

It is a tau number, because it is divible by the number of its divisors (8).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81163706879) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 5072731672 + ... + 5072731687.

It is an arithmetic number, because the mean of its divisors is an integer number (19022743800).

Almost surely, 2^81163706872 is an apocalyptic number.

It is an amenable number.

81163706872 is a deficient number, since it is larger than the sum of its proper divisors (71018243528).

81163706872 is a wasteful number, since it uses less digits than its factorization.

81163706872 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10145463365 (or 10145463361 counting only the distinct ones).

The product of its (nonzero) digits is 677376, while the sum is 49.

The spelling of 81163706872 in words is "eighty-one billion, one hundred sixty-three million, seven hundred six thousand, eight hundred seventy-two".