68912821 has 2 divisors, whose sum is σ = 68912822. Its totient is φ = 68912820.

The previous prime is 68912797. The next prime is 68912839. The reversal of 68912821 is 12821986.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 68657796 + 255025 = 8286^2 + 505^2 .

It is a cyclic number.

It is not a de Polignac number, because 68912821 - 2⁹ = 68912309 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (68912881) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 34456410 + 34456411.

It is an arithmetic number, because the mean of its divisors is an integer number (34456411).

Almost surely, 2^68912821 is an apocalyptic number.

It is an amenable number.

68912821 is a deficient number, since it is larger than the sum of its proper divisors (1).

68912821 is an equidigital number, since it uses as much as digits as its factorization.

68912821 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 13824, while the sum is 37.

The square root of 68912821 is about 8301.3746452018. The cubic root of 68912821 is about 409.9837808377.

The spelling of 68912821 in words is "sixty-eight million, nine hundred twelve thousand, eight hundred twenty-one".