68248721 has 4 divisors (see below), whose sum is σ = 68265252. Its totient is φ = 68232192.

The previous prime is 68248717. The next prime is 68248753. The reversal of 68248721 is 12784286.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length, and also an emirpimes, since its reverse is a distinct semiprime: 12784286 = 2 ⋅6392143.

It can be written as a sum of positive squares in 2 ways, for example, as 56415121 + 11833600 = 7511^2 + 3440^2 .

It is a cyclic number.

It is not a de Polignac number, because 68248721 - 2² = 68248717 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (68248771) 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, 3761 + ... + 12273.

It is an arithmetic number, because the mean of its divisors is an integer number (17066313).

Almost surely, 2^68248721 is an apocalyptic number.

It is an amenable number.

68248721 is a deficient number, since it is larger than the sum of its proper divisors (16531).

68248721 is an equidigital number, since it uses as much as digits as its factorization.

68248721 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 16530.

The product of its digits is 43008, while the sum is 38.

The square root of 68248721 is about 8261.2784119651. The cubic root of 68248721 is about 408.6625484775.

The spelling of 68248721 in words is "sixty-eight million, two hundred forty-eight thousand, seven hundred twenty-one".