81720112 has 10 divisors (see below), whose sum is σ = 158332748. Its totient is φ = 40860048.

The previous prime is 81720109. The next prime is 81720137. The reversal of 81720112 is 21102718.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 2553738 + ... + 2553769.

Almost surely, 2^81720112 is an apocalyptic number.

It is an amenable number.

81720112 is a deficient number, since it is larger than the sum of its proper divisors (76612636).

81720112 is a wasteful number, since it uses less digits than its factorization.

81720112 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5107515 (or 5107509 counting only the distinct ones).

The product of its (nonzero) digits is 224, while the sum is 22.

The square root of 81720112 is about 9039.9176987404. The cubic root of 81720112 is about 433.9532890896.

The spelling of 81720112 in words is "eighty-one million, seven hundred twenty thousand, one hundred twelve".