68721 has 4 divisors (see below), whose sum is σ = 91632. Its totient is φ = 45812.

The previous prime is 68713. The next prime is 68729. The reversal of 68721 is 12786.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is an interprime number because it is at equal distance from previous prime (68713) and next prime (68729).

It is a cyclic number.

It is not a de Polignac number, because 68721 - 2³ = 68713 is a prime.

It is a D-number.

It is a Curzon number.

It is a plaindrome in base 15.

It is a junction number, because it is equal to n+sod(n) for n = 68691 and 68700.

It is not an unprimeable number, because it can be changed into a prime (68729) 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 3 ways as a sum of consecutive naturals, for example, 11451 + ... + 11456.

It is an arithmetic number, because the mean of its divisors is an integer number (22908).

2⁶⁸⁷²¹ is an apocalyptic number.

It is an amenable number.

68721 is a deficient number, since it is larger than the sum of its proper divisors (22911).

68721 is a wasteful number, since it uses less digits than its factorization.

68721 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 22910.

The product of its digits is 672, while the sum is 24.

The square root of 68721 is about 262.1469053794. The cubic root of 68721 is about 40.9603026431.

It can be divided in two parts, 6 and 8721, that multiplied together give a triangular number (52326 = T₃₂₃).

The spelling of 68721 in words is "sixty-eight thousand, seven hundred twenty-one".