68166517813 has 4 divisors (see below), whose sum is σ = 68314384908. Its totient is φ = 68018650720.

The previous prime is 68166517763. The next prime is 68166517823. The reversal of 68166517813 is 31871566186.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 31871566186 = 2 ⋅15935783093.

It can be written as a sum of positive squares in 2 ways, for example, as 52103997169 + 16062520644 = 228263^2 + 126738^2 .

It is a cyclic number.

It is not a de Polignac number, because 68166517813 - 2¹⁷ = 68166386741 is a prime.

It is a super-3 number, since 3×68166517813³ (a number of 33 digits) contains 333 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (68166517823) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 73932856 + ... + 73933777.

It is an arithmetic number, because the mean of its divisors is an integer number (17078596227).

Almost surely, 2^68166517813 is an apocalyptic number.

It is an amenable number.

68166517813 is a deficient number, since it is larger than the sum of its proper divisors (147867095).

68166517813 is a wasteful number, since it uses less digits than its factorization.

68166517813 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 147867094.

The product of its digits is 1451520, while the sum is 52.

The spelling of 68166517813 in words is "sixty-eight billion, one hundred sixty-six million, five hundred seventeen thousand, eight hundred thirteen".