68289721 has 4 divisors (see below), whose sum is σ = 68952832. Its totient is φ = 67626612.

The previous prime is 68289713. The next prime is 68289763. The reversal of 68289721 is 12798286.

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 a cyclic number.

It is not a de Polignac number, because 68289721 - 2³ = 68289713 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (68289421) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 331401 + ... + 331606.

It is an arithmetic number, because the mean of its divisors is an integer number (17238208).

Almost surely, 2^68289721 is an apocalyptic number.

It is an amenable number.

68289721 is a deficient number, since it is larger than the sum of its proper divisors (663111).

68289721 is a wasteful number, since it uses less digits than its factorization.

68289721 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 663110.

The product of its digits is 96768, while the sum is 43.

The square root of 68289721 is about 8263.7594955323. The cubic root of 68289721 is about 408.7443659347.

The spelling of 68289721 in words is "sixty-eight million, two hundred eighty-nine thousand, seven hundred twenty-one".