68917561 has 4 divisors (see below), whose sum is σ = 69022800. Its totient is φ = 68812324.

The previous prime is 68917559. The next prime is 68917567. The reversal of 68917561 is 16571986.

It is a happy number.

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: 16571986 = 2 ⋅8285993.

It is a cyclic number.

It is not a de Polignac number, because 68917561 - 2¹ = 68917559 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (68917567) 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, 51631 + ... + 52948.

It is an arithmetic number, because the mean of its divisors is an integer number (17255700).

Almost surely, 2^68917561 is an apocalyptic number.

It is an amenable number.

68917561 is a deficient number, since it is larger than the sum of its proper divisors (105239).

68917561 is a wasteful number, since it uses less digits than its factorization.

68917561 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 105238.

The product of its digits is 90720, while the sum is 43.

The square root of 68917561 is about 8301.6601351778. The cubic root of 68917561 is about 409.9931805330.

The spelling of 68917561 in words is "sixty-eight million, nine hundred seventeen thousand, five hundred sixty-one".