68042521 has 4 divisors (see below), whose sum is σ = 68703232. Its totient is φ = 67381812.

The previous prime is 68042479. The next prime is 68042531. The reversal of 68042521 is 12524086.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also an emirpimes, since its reverse is a distinct semiprime: 12524086 = 2 ⋅6262043.

It is a cyclic number.

It is not a de Polignac number, because 68042521 - 2¹⁹ = 67518233 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 68042521.

It is not an unprimeable number, because it can be changed into a prime (68042531) 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 in 3 ways as a sum of consecutive naturals, for example, 330201 + ... + 330406.

It is an arithmetic number, because the mean of its divisors is an integer number (17175808).

Almost surely, 2^68042521 is an apocalyptic number.

It is an amenable number.

68042521 is a deficient number, since it is larger than the sum of its proper divisors (660711).

68042521 is a wasteful number, since it uses less digits than its factorization.

68042521 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 660710.

The product of its (nonzero) digits is 3840, while the sum is 28.

The square root of 68042521 is about 8248.7890626443. The cubic root of 68042521 is about 408.2505689632.

The spelling of 68042521 in words is "sixty-eight million, forty-two thousand, five hundred twenty-one".