68613521 has 2 divisors, whose sum is σ = 68613522. Its totient is φ = 68613520.

The previous prime is 68613499. The next prime is 68613539. The reversal of 68613521 is 12531686.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 53875600 + 14737921 = 7340^2 + 3839^2 .

It is a cyclic number.

It is not a de Polignac number, because 68613521 - 2¹⁰ = 68612497 is a prime.

It is not a weakly prime, because it can be changed into another prime (68613221) 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, 34306760 + 34306761.

It is an arithmetic number, because the mean of its divisors is an integer number (34306761).

Almost surely, 2^68613521 is an apocalyptic number.

It is an amenable number.

68613521 is a deficient number, since it is larger than the sum of its proper divisors (1).

68613521 is an equidigital number, since it uses as much as digits as its factorization.

68613521 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 8640, while the sum is 32.

The square root of 68613521 is about 8283.3278940291. The cubic root of 68613521 is about 409.3893765788.

The spelling of 68613521 in words is "sixty-eight million, six hundred thirteen thousand, five hundred twenty-one".