68938721 has 4 divisors (see below), whose sum is σ = 69769392. Its totient is φ = 68108052.

The previous prime is 68938711. The next prime is 68938729. The reversal of 68938721 is 12783986.

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 a de Polignac number, because none of the positive numbers 2^k-68938721 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (68938729) 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, 415211 + ... + 415376.

It is an arithmetic number, because the mean of its divisors is an integer number (17442348).

Almost surely, 2^68938721 is an apocalyptic number.

It is an amenable number.

68938721 is a deficient number, since it is larger than the sum of its proper divisors (830671).

68938721 is an equidigital number, since it uses as much as digits as its factorization.

68938721 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 830670.

The product of its digits is 145152, while the sum is 44.

The square root of 68938721 is about 8302.9344812542. The cubic root of 68938721 is about 410.0351367864.

The spelling of 68938721 in words is "sixty-eight million, nine hundred thirty-eight thousand, seven hundred twenty-one".