68284721 has 8 divisors (see below), whose sum is σ = 71842344. Its totient is φ = 64817280.

The previous prime is 68284717. The next prime is 68284753. The reversal of 68284721 is 12748286.

It can be written as a sum of positive squares in 4 ways, for example, as 57121 + 68227600 = 239^2 + 8260^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 68284721 - 2² = 68284717 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (68284421) 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 7 ways as a sum of consecutive naturals, for example, 20990 + ... + 24023.

It is an arithmetic number, because the mean of its divisors is an integer number (8980293).

Almost surely, 2^68284721 is an apocalyptic number.

It is an amenable number.

68284721 is a deficient number, since it is larger than the sum of its proper divisors (3557623).

68284721 is a wasteful number, since it uses less digits than its factorization.

68284721 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 45091.

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

The square root of 68284721 is about 8263.4569642493. The cubic root of 68284721 is about 408.7343899496.

The spelling of 68284721 in words is "sixty-eight million, two hundred eighty-four thousand, seven hundred twenty-one".