68516521 has 2 divisors, whose sum is σ = 68516522. Its totient is φ = 68516520.

The previous prime is 68516519. The next prime is 68516543. The reversal of 68516521 is 12561586.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 58308496 + 10208025 = 7636^2 + 3195^2 .

It is a cyclic number.

It is not a de Polignac number, because 68516521 - 2¹ = 68516519 is a prime.

Together with 68516519, it forms a pair of twin primes.

It is not a weakly prime, because it can be changed into another prime (68516551) 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, 34258260 + 34258261.

It is an arithmetic number, because the mean of its divisors is an integer number (34258261).

Almost surely, 2^68516521 is an apocalyptic number.

It is an amenable number.

68516521 is a deficient number, since it is larger than the sum of its proper divisors (1).

68516521 is an equidigital number, since it uses as much as digits as its factorization.

68516521 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 14400, while the sum is 34.

The square root of 68516521 is about 8277.4706885618. The cubic root of 68516521 is about 409.1963655566.

The spelling of 68516521 in words is "sixty-eight million, five hundred sixteen thousand, five hundred twenty-one".