68312721 has 16 divisors (see below), whose sum is σ = 93080448. Its totient is φ = 44553600.

The previous prime is 68312689. The next prime is 68312729. The reversal of 68312721 is 12721386.

It is not a de Polignac number, because 68312721 - 2⁵ = 68312689 is a prime.

It is not an unprimeable number, because it can be changed into a prime (68312729) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 28011 + ... + 30351.

It is an arithmetic number, because the mean of its divisors is an integer number (5817528).

Almost surely, 2^68312721 is an apocalyptic number.

It is an amenable number.

68312721 is a deficient number, since it is larger than the sum of its proper divisors (24767727).

68312721 is a wasteful number, since it uses less digits than its factorization.

68312721 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2552.

The product of its digits is 4032, while the sum is 30.

The square root of 68312721 is about 8265.1509968058. The cubic root of 68312721 is about 408.7902491952.

The spelling of 68312721 in words is "sixty-eight million, three hundred twelve thousand, seven hundred twenty-one".