80721 has 6 divisors (see below), whose sum is σ = 116610. Its totient is φ = 53808.

The previous prime is 80713. The next prime is 80737. The reversal of 80721 is 12708.

It can be written as a sum of positive squares in only one way, i.e., 69696 + 11025 = 264^2 + 105^2 .

It is not a de Polignac number, because 80721 - 2³ = 80713 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 80694 and 80703.

It is not an unprimeable number, because it can be changed into a prime (80701) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 4476 + ... + 4493.

It is an arithmetic number, because the mean of its divisors is an integer number (19435).

2⁸⁰⁷²¹ is an apocalyptic number.

It is an amenable number.

80721 is a deficient number, since it is larger than the sum of its proper divisors (35889).

80721 is a wasteful number, since it uses less digits than its factorization.

80721 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 8975 (or 8972 counting only the distinct ones).

The product of its (nonzero) digits is 112, while the sum is 18.

The square root of 80721 is about 284.1144135731. The cubic root of 80721 is about 43.2177524775.

It can be divided in two parts, 807 and 21, that added together give a palindrome (828).

The spelling of 80721 in words is "eighty thousand, seven hundred twenty-one".