81728703 has 64 divisors (see below), whose sum is σ = 145152000. Its totient is φ = 44478720.

The previous prime is 81728701. The next prime is 81728771. The reversal of 81728703 is 30782718.

It is not a de Polignac number, because 81728703 - 2¹ = 81728701 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81728701) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 410598 + ... + 410796.

It is an arithmetic number, because the mean of its divisors is an integer number (2268000).

Almost surely, 2^81728703 is an apocalyptic number.

81728703 is a deficient number, since it is larger than the sum of its proper divisors (63423297).

81728703 is a wasteful number, since it uses less digits than its factorization.

81728703 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 309 (or 303 counting only the distinct ones).

The product of its (nonzero) digits is 18816, while the sum is 36.

The square root of 81728703 is about 9040.3928565080. The cubic root of 81728703 is about 433.9684953098.

The spelling of 81728703 in words is "eighty-one million, seven hundred twenty-eight thousand, seven hundred three".