80821728 has 72 divisors (see below), whose sum is σ = 247528008. Its totient is φ = 24867072.

The previous prime is 80821721. The next prime is 80821729. The reversal of 80821728 is 82712808.

It is a tau number, because it is divible by the number of its divisors (72).

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a junction number, because it is equal to n+sod(n) for n = 80821692 and 80821701.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (80821721) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 7050 + ... + 14537.

It is an arithmetic number, because the mean of its divisors is an integer number (3437889).

Almost surely, 2^80821728 is an apocalyptic number.

It is an amenable number.

80821728 is an abundant number, since it is smaller than the sum of its proper divisors (166706280).

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

80821728 is a wasteful number, since it uses less digits than its factorization.

80821728 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 21616 (or 21605 counting only the distinct ones).

The product of its (nonzero) digits is 14336, while the sum is 36.

The square root of 80821728 is about 8990.0905445941. The cubic root of 80821728 is about 432.3572148306.

The spelling of 80821728 in words is "eighty million, eight hundred twenty-one thousand, seven hundred twenty-eight".