83721 has 16 divisors (see below), whose sum is σ = 126720. Its totient is φ = 48720.

The previous prime is 83719. The next prime is 83737. The reversal of 83721 is 12738.

It is not a de Polignac number, because 83721 - 2¹ = 83719 is a prime.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (83701) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 1390 + ... + 1448.

It is an arithmetic number, because the mean of its divisors is an integer number (7920).

2⁸³⁷²¹ is an apocalyptic number.

It is an amenable number.

83721 is a deficient number, since it is larger than the sum of its proper divisors (42999).

83721 is a wasteful number, since it uses less digits than its factorization.

83721 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 116.

The product of its digits is 336, while the sum is 21.

The square root of 83721 is about 289.3458138629. The cubic root of 83721 is about 43.7466500836.

It can be divided in two parts, 837 and 21, that added together give a palindrome (858).

The spelling of 83721 in words is "eighty-three thousand, seven hundred twenty-one".