81728746 has 8 divisors (see below), whose sum is σ = 133737984. Its totient is φ = 37149420.

The previous prime is 81728701. The next prime is 81728771. The reversal of 81728746 is 64782718.

It is a sphenic number, since it is the product of 3 distinct primes.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1857450 + ... + 1857493.

It is an arithmetic number, because the mean of its divisors is an integer number (16717248).

Almost surely, 2^81728746 is an apocalyptic number.

81728746 is a deficient number, since it is larger than the sum of its proper divisors (52009238).

81728746 is a wasteful number, since it uses less digits than its factorization.

81728746 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3714956.

The product of its digits is 150528, while the sum is 43.

The square root of 81728746 is about 9040.3952347229. The cubic root of 81728746 is about 433.9685714179.

It can be divided in two parts, 81 and 728746, that added together give a palindrome (728827).

The spelling of 81728746 in words is "eighty-one million, seven hundred twenty-eight thousand, seven hundred forty-six".